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• SQL SERVER – Understanding ALTER INDEX ALL REBUILD with Disabled Clustered Index

  - by pinaldave

  This blog is in response to the ongoing communication with the reader who had earlier asked the question of SQL SERVER – Disable Clustered Index and Data Insert. The same reader has asked me the difference between ALTER INDEX ALL REBUILD and ALTER INDEX REBUILD along with disabled clustered index. Instead of writing a big theory, we will go over the demo right away. Here are the steps that we intend to follow. 1) Create Clustered and Nonclustered Index 2) Disable Clustered and Nonclustered Index 3) Enable – a) All Indexes, b) Clustered Index USE tempdb GO -- Drop Table if Exists IF EXISTS (SELECT * FROM sys.objects WHERE OBJECT_ID = OBJECT_ID(N'[dbo].[TableName]') AND type IN (N'U')) DROP TABLE [dbo].[TableName] GO -- Create Table CREATE TABLE [dbo].[TableName]( [ID] [int] NOT NULL, [FirstCol] [varchar](50) NULL ) GO -- Create Clustered Index ALTER TABLE [TableName] ADD CONSTRAINT [PK_TableName] PRIMARY KEY CLUSTERED ([ID] ASC) GO -- Create Nonclustered Index CREATE UNIQUE NONCLUSTERED INDEX [IX_NonClustered_TableName] ON [dbo].[TableName] ([FirstCol] ASC) GO -- Check that all the indexes are enabled SELECT OBJECT_NAME(OBJECT_ID), Name, type_desc, is_disabled FROM sys.indexes WHERE OBJECT_NAME(OBJECT_ID) = 'TableName' GO Now let us disable both the indexes. -- Disable Indexes -- Disable Nonclustered Index ALTER INDEX [IX_NonClustered_TableName] ON [dbo].[TableName] DISABLE GO -- Disable Clustered Index ALTER INDEX [PK_TableName] ON [dbo].[TableName] DISABLE GO -- Check that all the indexes are disabled SELECT OBJECT_NAME(OBJECT_ID), Name, type_desc, is_disabled FROM sys.indexes WHERE OBJECT_NAME(OBJECT_ID) = 'TableName' GO Next, let us rebuild all the indexes and see the output. -- Test 1: ALTER INDEX ALL REBUILD -- Rebuliding should work fine ALTER INDEX ALL ON [dbo].[TableName] REBUILD GO -- Check that all the indexes are enabled SELECT OBJECT_NAME(OBJECT_ID), Name, type_desc, is_disabled FROM sys.indexes WHERE OBJECT_NAME(OBJECT_ID) = 'TableName' GO Now, once again disable indexes for the second test. -- Disable Indexes -- Disable Nonclustered Index ALTER INDEX [IX_NonClustered_TableName] ON [dbo].[TableName] DISABLE GO -- Disable Clustered Index ALTER INDEX [PK_TableName] ON [dbo].[TableName] DISABLE GO -- Check that all the indexes are disabled SELECT OBJECT_NAME(OBJECT_ID), Name, type_desc, is_disabled FROM sys.indexes WHERE OBJECT_NAME(OBJECT_ID) = 'TableName' GO Next, let us build only the clustered index and see the output of all the indexes. -- Test 2: ALTER INDEX REBUILD -- Rebuliding should work fine ALTER INDEX [PK_TableName] ON [dbo].[TableName] REBUILD GO -- Check that only clustered index is enabled SELECT OBJECT_NAME(OBJECT_ID), Name, type_desc, is_disabled FROM sys.indexes WHERE OBJECT_NAME(OBJECT_ID) = 'TableName' GO Let us do final clean up. -- Clean up DROP TABLE [TableName] GO From the example, it is very clear that if you have built only clustered index when the nonclustered index is disabled, it still remains disabled. Do let me know if the idea is clear. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Solution – Puzzle – SELECT * vs SELECT COUNT(*)

  - by pinaldave

  Earlier I have published Puzzle Why SELECT * throws an error but SELECT COUNT(*) does not. This question have received many interesting comments. Let us go over few of the answers, which are valid. Before I start the same, let me acknowledge Rob Farley who has not only answered correctly very first but also started interesting conversation in the same thread. The usual question will be what is the right answer. I would like to point to official Microsoft Connect Items which discusses the same. RGarvao https://connect.microsoft.com/SQLServer/feedback/details/671475/select-test-where-exists-select tiberiu utan http://connect.microsoft.com/SQLServer/feedback/details/338532/count-returns-a-value-1 Rob Farley count(*) is about counting rows, not a particular column. It doesn’t even look to see what columns are available, it’ll just count the rows, which in the case of a missing FROM clause, is 1. “select *” is designed to return columns, and therefore barfs if there are none available. Even more odd is this one: select ‘blah’ where exists (select *) You might be surprised at the results… Koushik The engine performs a “Constant scan” for Count(*) where as in the case of “SELECT *” the engine is trying to perform either Index/Cluster/Table scans. amikolaj When you query ‘select * from sometable’, SQL replaces * with the current schema of that table. With out a source for the schema, SQL throws an error. so when you query ‘select count(*)’, you are counting the one row. * is just a constant to SQL here. Check out the execution plan. Like the description states – ‘Scan an internal table of constants.’ You could do ‘select COUNT(‘my name is adam and this is my answer’)’ and get the same answer. Netra Acharya SELECT * Here, * represents all columns from a table. So it always looks for a table (As we know, there should be FROM clause before specifying table name). So, it throws an error whenever this condition is not satisfied. SELECT COUNT(*) Here, COUNT is a Function. So it is not mandetory to provide a table. Check it out this: DECLARE @cnt INT SET @cnt = COUNT(*) SELECT @cnt SET @cnt = COUNT(‘x’) SELECT @cnt Naveen Select 1 / Select ‘*’ will return 1/* as expected. Select Count(1)/Count(*) will return the count of result set of select statement. Count(1)/Count(*) will have one 1/* for each row in the result set of select statement. Select 1 or Select ‘*’ result set will contain only 1 result. so count is 1. Where as “Select *” is a sysntax which expects the table or equauivalent to table (table functions, etc..). It is like compilation error for that query. Ramesh Hi Friends, Count is an aggregate function and it expects the rows (list of records) for a specified single column or whole rows for *. So, when we use ‘select *’ it definitely give and error because ‘*’ is meant to have all the fields but there is not any table and without table it can only raise an error. So, in the case of ‘Select Count(*)’, there will be an error as a record in the count function so you will get the result as ’1'. Try using : Select COUNT(‘RAMESH’) and think there is an error ‘Must specify table to select from.’ in place of ‘RAMESH’ Pinal : If i am wrong then please clarify this. Sachin Nandanwar Any aggregate function expects a constant or a column name as an expression. DO NOT be confused with * in an aggregate function.The aggregate function does not treat it as a column name or a set of column names but a constant value, as * is a key word in SQL. You can replace any value instead of * for the COUNT function.Ex Select COUNT(5) will result as 1. The error resulting from select * is obvious it expects an object where it can extract the result set. I sincerely thank you all for wonderful conversation, I personally enjoyed it and I am sure all of you have the same feeling. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: CodeProject, Pinal Dave, PostADay, Readers Contribution, Readers Question, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQL SERVER – A Puzzle – Fun with NULL – Fix Error 8117

  - by pinaldave

  During my 8 years of career, I have been involved in many interviews. Quite often, I act as the  interview. If I am the interviewer, I ask many questions – from easy questions to difficult ones. When I am the interviewee, I frequently get an opportunity to ask the interviewer some questions back. Regardless of the my capacity in attending the interview, I always make it a point to ask the interviewer at least one question. What is NULL? It’s always fun to ask this question during interviews, because in every interview, I get a different answer. NULL is often confused with false, absence of value or infinite value. Honestly, NULL is a very interesting subject as it bases its behavior in server settings. There are a few properties of NULL that are universal, but the knowledge about these properties is not known in a universal sense. Let us run this simple puzzle. Run the following T-SQL script: SELECT SUM(data) FROM (SELECT NULL AS data) t It will return the following error: Msg 8117, Level 16, State 1, Line 1 Operand data type NULL is invalid for sum operator. Now the error makes it very clear that NULL is invalid for sum Operator. Frequently enough, I have showed this simple query to many folks whom I came across. I asked them if they could modify the subquery and return the result as NULL. Here is what I expected: Even though this is a very simple looking query, so far I’ve got the correct answer from only 10% of the people to whom I have asked this question. It was common for me to receive this kind of answer – convert the NULL to some data type. However, doing so usually returns the value as 0 or the integer they passed. SELECT SUM(data) FROM (SELECT ISNULL(NULL,0) AS data) t I usually see many people modifying the outer query to get desired NULL result, but that is not allowed in this simple puzzle. This small puzzle made me wonder how many people have a clear understanding about NULL. Well, here is the answer to my simple puzzle. Just CAST NULL AS INT and it will return the final result as NULL: SELECT SUM(data) FROM (SELECT CAST(NULL AS INT) AS data) t Now that you know the answer, don’t you think it was very simple indeed? This blog post is especially dedicated to my friend Madhivanan who has written an excellent blog post about NULL. I am confident that after reading the blog post from Madhivanan, you will have no confusion regarding NULL in the future. Read: NULL, NULL, NULL and nothing but NULL. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Updating Data in A Columnstore Index

  - by pinaldave

  So far I have written two articles on Columnstore Indexes, and both of them got very interesting readership. In fact, just recently I got a query on my previous article on Columnstore Index. Read the following two articles to get familiar with the Columnstore Index. They will give you a reference to the question which was asked by a certain reader: SQL SERVER – Fundamentals of Columnstore Index SQL SERVER – How to Ignore Columnstore Index Usage in Query Here is the reader’s question: ” When I tried to update my table after creating the Columnstore index, it gives me an error. What should I do?” When the Columnstore index is created on the table, the table becomes Read-Only table and it does not let any insert/update/delete on the table. The basic understanding is that Columnstore Index will be created on the table that is very huge and holds lots of data. If a table is small enough, there is no need to create a Columnstore index. The regular index should just help it. The reason why Columnstore index was needed is because the table was so big that retrieving the data was taking a really, really long time. Now, updating such a huge table is always a challenge by itself. If the Columnstore Index is created on the table, and the table needs to be updated, you need to know that there are various ways to update it. The easiest way is to disable the Index and enable it. Consider the following code: USE AdventureWorks GO -- Create New Table CREATE TABLE [dbo].[MySalesOrderDetail]( [SalesOrderID] [int] NOT NULL, [SalesOrderDetailID] [int] NOT NULL, [CarrierTrackingNumber] [nvarchar](25) NULL, [OrderQty] [smallint] NOT NULL, [ProductID] [int] NOT NULL, [SpecialOfferID] [int] NOT NULL, [UnitPrice] [money] NOT NULL, [UnitPriceDiscount] [money] NOT NULL, [LineTotal] [numeric](38, 6) NOT NULL, [rowguid] [uniqueidentifier] NOT NULL, [ModifiedDate] [datetime] NOT NULL ) ON [PRIMARY] GO -- Create clustered index CREATE CLUSTERED INDEX [CL_MySalesOrderDetail] ON [dbo].[MySalesOrderDetail] ( [SalesOrderDetailID]) GO -- Create Sample Data Table -- WARNING: This Query may run upto 2-10 minutes based on your systems resources INSERT INTO [dbo].[MySalesOrderDetail] SELECT S1.* FROM Sales.SalesOrderDetail S1 GO 100 -- Create ColumnStore Index CREATE NONCLUSTERED COLUMNSTORE INDEX [IX_MySalesOrderDetail_ColumnStore] ON [MySalesOrderDetail] (UnitPrice, OrderQty, ProductID) GO -- Attempt to Update the table UPDATE [dbo].[MySalesOrderDetail] SET OrderQty = OrderQty +1 WHERE [SalesOrderID] = 43659 GO /* It will throw following error Msg 35330, Level 15, State 1, Line 2 UPDATE statement failed because data cannot be updated in a table with a columnstore index. Consider disabling the columnstore index before issuing the UPDATE statement, then rebuilding the columnstore index after UPDATE is complete. */ A similar error also shows up for Insert/Delete function. Here is the workaround. Disable the Columnstore Index and performance update, enable the Columnstore Index: -- Disable the Columnstore Index ALTER INDEX [IX_MySalesOrderDetail_ColumnStore] ON [dbo].[MySalesOrderDetail] DISABLE GO -- Attempt to Update the table UPDATE [dbo].[MySalesOrderDetail] SET OrderQty = OrderQty +1 WHERE [SalesOrderID] = 43659 GO -- Rebuild the Columnstore Index ALTER INDEX [IX_MySalesOrderDetail_ColumnStore] ON [dbo].[MySalesOrderDetail] REBUILD GO This time it will not throw an error while the update of the table goes successfully. Let us do a cleanup of our tables using this code: -- Cleanup DROP INDEX [IX_MySalesOrderDetail_ColumnStore] ON [dbo].[MySalesOrderDetail] GO TRUNCATE TABLE dbo.MySalesOrderDetail GO DROP TABLE dbo.MySalesOrderDetail GO In the next post we will see how we can use Partition to update the Columnstore Index. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Simple Example of Snapshot Isolation – Reduce the Blocking Transactions

  - by pinaldave

  To learn any technology and move to a more advanced level, it is very important to understand the fundamentals of the subject first. Today, we will be talking about something which has been quite introduced a long time ago but not properly explored when it comes to the isolation level. Snapshot Isolation was introduced in SQL Server in 2005. However, the reality is that there are still many software shops which are using the SQL Server 2000, and therefore cannot be able to maintain the Snapshot Isolation. Many software shops have upgraded to the later version of the SQL Server, but their respective developers have not spend enough time to upgrade themselves with the latest technology. “It works!” is a very common answer of many when they are asked about utilizing the new technology, instead of backward compatibility commands. In one of the recent consultation project, I had same experience when developers have “heard about it” but have no idea about snapshot isolation. They were thinking it is the same as Snapshot Replication – which is plain wrong. This is the same demo I am including here which I have created for them. In Snapshot Isolation, the updated row versions for each transaction are maintained in TempDB. Once a transaction has begun, it ignores all the newer rows inserted or updated in the table. Let us examine this example which shows the simple demonstration. This transaction works on optimistic concurrency model. Since reading a certain transaction does not block writing transaction, it also does not block the reading transaction, which reduced the blocking. First, enable database to work with Snapshot Isolation. Additionally, check the existing values in the table from HumanResources.Shift. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO Now, we will need two different sessions to prove this example. First Session: Set Transaction level isolation to snapshot and begin the transaction. Update the column “ModifiedDate” to today’s date. -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO Please note that we have not yet been committed to the transaction. Now, open the second session and run the following “SELECT” statement. Then, check the values of the table. Please pay attention on setting the Isolation level for the second one as “Snapshot” at the same time when we already start the transaction using BEGIN TRAN. -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values in the table are still original values. They have not been modified yet. Once again, go back to session 1 and begin the transaction. -- Session 1 COMMIT After that, go back to Session 2 and see the values of the table. -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values are yet not changed and they are still the same old values which were there right in the beginning of the session. Now, let us commit the transaction in the session 2. Once committed, run the same SELECT statement once more and see what the result is. -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that it now reflects the new updated value. I hope that this example is clear enough as it would give you good idea how the Snapshot Isolation level works. There is much more to write about an extra level, READ_COMMITTED_SNAPSHOT, which we will be discussing in another post soon. If you wish to use this transaction’s Isolation level in your production database, I would appreciate your comments about their performance on your servers. I have included here the complete script used in this example for your quick reference. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 COMMIT -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Transaction Isolation

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• SQL SERVER – Simple Example of Snapshot Isolation – Reduce the Blocking Transactions

  - by pinaldave

  To learn any technology and move to a more advanced level, it is very important to understand the fundamentals of the subject first. Today, we will be talking about something which has been quite introduced a long time ago but not properly explored when it comes to the isolation level. Snapshot Isolation was introduced in SQL Server in 2005. However, the reality is that there are still many software shops which are using the SQL Server 2000, and therefore cannot be able to maintain the Snapshot Isolation. Many software shops have upgraded to the later version of the SQL Server, but their respective developers have not spend enough time to upgrade themselves with the latest technology. “It works!” is a very common answer of many when they are asked about utilizing the new technology, instead of backward compatibility commands. In one of the recent consultation project, I had same experience when developers have “heard about it” but have no idea about snapshot isolation. They were thinking it is the same as Snapshot Replication – which is plain wrong. This is the same demo I am including here which I have created for them. In Snapshot Isolation, the updated row versions for each transaction are maintained in TempDB. Once a transaction has begun, it ignores all the newer rows inserted or updated in the table. Let us examine this example which shows the simple demonstration. This transaction works on optimistic concurrency model. Since reading a certain transaction does not block writing transaction, it also does not block the reading transaction, which reduced the blocking. First, enable database to work with Snapshot Isolation. Additionally, check the existing values in the table from HumanResources.Shift. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO Now, we will need two different sessions to prove this example. First Session: Set Transaction level isolation to snapshot and begin the transaction. Update the column “ModifiedDate” to today’s date. -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO Please note that we have not yet been committed to the transaction. Now, open the second session and run the following “SELECT” statement. Then, check the values of the table. Please pay attention on setting the Isolation level for the second one as “Snapshot” at the same time when we already start the transaction using BEGIN TRAN. -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values in the table are still original values. They have not been modified yet. Once again, go back to session 1 and begin the transaction. -- Session 1 COMMIT After that, go back to Session 2 and see the values of the table. -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values are yet not changed and they are still the same old values which were there right in the beginning of the session. Now, let us commit the transaction in the session 2. Once committed, run the same SELECT statement once more and see what the result is. -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that it now reflects the new updated value. I hope that this example is clear enough as it would give you good idea how the Snapshot Isolation level works. There is much more to write about an extra level, READ_COMMITTED_SNAPSHOT, which we will be discussing in another post soon. If you wish to use this transaction’s Isolation level in your production database, I would appreciate your comments about their performance on your servers. I have included here the complete script used in this example for your quick reference. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 COMMIT -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Transaction Isolation

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• SQL SERVER – What is Incremental Statistics? – Performance improvements in SQL Server 2014 – Part 1

  - by Pinal Dave

  This is the first part of the series Incremental Statistics. Here is the index of the complete series. What is Incremental Statistics? – Performance improvements in SQL Server 2014 – Part 1 Simple Example of Incremental Statistics – Performance improvements in SQL Server 2014 – Part 2 DMV to Identify Incremental Statistics – Performance improvements in SQL Server 2014 – Part 3 Statistics are considered one of the most important aspects of SQL Server Performance Tuning. You might have often heard the phrase, with related to performance tuning. “Update Statistics before you take any other steps to tune performance”. Honestly, I have said above statement many times and many times, I have personally updated statistics before I start to do any performance tuning exercise. You may agree or disagree to the point, but there is no denial that Statistics play an extremely vital role in the performance tuning. SQL Server 2014 has a new feature called Incremental Statistics. I have been playing with this feature for quite a while and I find that very interesting. After spending some time with this feature, I decided to write about this subject over here. New in SQL Server 2014 – Incremental Statistics Well, it seems like lots of people wants to start using SQL Server 2014′s new feature of Incremetnal Statistics. However, let us understand what actually this feature does and how it can help. I will try to simplify this feature first before I start working on the demo code. Code for all versions of SQL Server Here is the code which you can execute on all versions of SQL Server and it will update the statistics of your table. The keyword which you should pay attention is WITH FULLSCAN. It will scan the entire table and build brand new statistics for you which your SQL Server Performance Tuning engine can use for better estimation of your execution plan. UPDATE STATISTICS TableName(StatisticsName) WITH FULLSCAN Who should learn about this? Why? If you are using partitions in your database, you should consider about implementing this feature. Otherwise, this feature is pretty much not applicable to you. Well, if you are using single partition and your table data is in a single place, you still have to update your statistics the same way you have been doing. If you are using multiple partitions, this may be a very useful feature for you. In most cases, users have multiple partitions because they have lots of data in their table. Each partition will have data which belongs to itself. Now it is very common that each partition are populated separately in SQL Server. Real World Example For example, if your table contains data which is related to sales, you will have plenty of entries in your table. It will be a good idea to divide the partition into multiple filegroups for example, you can divide this table into 3 semesters or 4 quarters or even 12 months. Let us assume that we have divided our table into 12 different partitions. Now for the month of January, our first partition will be populated and for the month of February our second partition will be populated. Now assume, that you have plenty of the data in your first and second partition. Now the month of March has just started and your third partition has started to populate. Due to some reason, if you want to update your statistics, what will you do? In SQL Server 2012 and earlier version You will just use the code of WITH FULLSCAN and update the entire table. That means even though you have only data in third partition you will still update the entire table. This will be VERY resource intensive process as you will be updating the statistics of the partition 1 and 2 where data has not changed at all. In SQL Server 2014 You will just update the partition of Partition 3. There is a special syntax where you can now specify which partition you want to update now. The impact of this is that it is smartly merging the new data with old statistics and update the entire statistics without doing FULLSCAN of your entire table. This has a huge impact on performance. Remember that the new feature in SQL Server 2014 does not change anything besides the capability to update a single partition. However, there is one feature which is indeed attractive. Previously, when table data were changed 20% at that time, statistics update were triggered. However, now the same threshold is applicable to a single partition. That means if your partition faces 20% data, change it will also trigger partition level statistics update which, when merged to your final statistics will give you better performance. In summary If you are not using a partition, this feature is not applicable to you. If you are using a partition, this feature can be very helpful to you. Tomorrow: We will see working code of SQL Server 2014 Incremental Statistics. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SQL Statistics, Statistics

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• SQL SERVER – Size of Index Table for Each Index – Solution 3 – Powershell

  - by pinaldave

  Laerte Junior If you are a Powershell user, the name of the Laerte Junior is not a new name. He is the one man with exceptional knowledge of Powershell. He is not only very knowledgeable, but also very kind and eager to those in need. I have been attempting to setup Powershell for many days, but constantly facing issues. I was not able to get going with this tool. Finally, yesterday I sent email to Laerte in response to his comment posted here. Within 5 minutes, Laerte came online and helped me with the solution. He spend nearly 15 minutes working along with me to solve my problem with installation. And yes, he did resolve it remotely without looking at my screen – What a skilled and exceptional person!! I will soon post a detail note about the issue I faced and resolved with the help of Laerte. Here is his solution to my earlier puzzle in his own words. Read the original puzzle here and Laerte’s solution from here. Hi Pinal, I do not say better, but maybe another approach to enthusiasts in powershell and SQLSPX library would be: 1 – All indexes in all tables and all databases Get-SqlDatabase -sqlserver “Yourserver” | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused 2 – All Indexes in all tables and specific database Get-SqlDatabase -sqlserver “Yourserver” “Yourdb” | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused 3 – All Indexes in specific table and database Get-SqlDatabase -sqlserver “Yourserver” “Yourdb” | Get-SqlTable “YourTable” | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused and to output to txt.. pipe Out-File Get-SqlDatabase -sqlserver “Yourserver” | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused | out-file c:\IndexesSize.txt If you have one txt with all your servers, can be for all of them also. Lets say you have all your servers in servers.txt: something like NameServer1 NameServer2 NameServer3 NameServer4 We could Use : foreach ($Server in Get-content c:\temp\servers.txt) { Get-SqlDatabase -sqlserver $Server | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused } :) After fixing my issue with Powershell, I ran Laerte‘s second suggestion – “All Indexes in all tables and specific database” and found the following accurate output. Click to Enlarge Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Powershell

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• SQL SERVER – Size of Index Table for Each Index – Solution 3 – Powershell

  - by pinaldave

  Laerte Junior If you are a Powershell user, the name of the Laerte Junior is not a new name. He is the one man with exceptional knowledge of Powershell. He is not only very knowledgeable, but also very kind and eager to those in need. I have been attempting to setup Powershell for many days, but constantly facing issues. I was not able to get going with this tool. Finally, yesterday I sent email to Laerte in response to his comment posted here. Within 5 minutes, Laerte came online and helped me with the solution. He spend nearly 15 minutes working along with me to solve my problem with installation. And yes, he did resolve it remotely without looking at my screen – What a skilled and exceptional person!! I will soon post a detail note about the issue I faced and resolved with the help of Laerte. Here is his solution to my earlier puzzle in his own words. Read the original puzzle here and Laerte’s solution from here. Hi Pinal, I do not say better, but maybe another approach to enthusiasts in powershell and SQLSPX library would be: 1 – All indexes in all tables and all databases Get-SqlDatabase -sqlserver “Yourserver” | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused 2 – All Indexes in all tables and specific database Get-SqlDatabase -sqlserver “Yourserver” “Yourdb” | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused 3 – All Indexes in specific table and database Get-SqlDatabase -sqlserver “Yourserver” “Yourdb” | Get-SqlTable “YourTable” | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused and to output to txt.. pipe Out-File Get-SqlDatabase -sqlserver “Yourserver” | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused | out-file c:\IndexesSize.txt If you have one txt with all your servers, can be for all of them also. Lets say you have all your servers in servers.txt: something like NameServer1 NameServer2 NameServer3 NameServer4 We could Use : foreach ($Server in Get-content c:\temp\servers.txt) { Get-SqlDatabase -sqlserver $Server | Get-SqlTable | Get-SqlIndex | Format-table Server,dbname,schema,table,name,id,spaceused } :) After fixing my issue with Powershell, I ran Laerte‘s second suggestion – “All Indexes in all tables and specific database” and found the following accurate output. Click to Enlarge Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Powershell

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• SQL SERVER – What is AdventureWorks?

  - by pinaldave

  NOTE: If you know the answer of this question, then I request you to stop reading this post right now. Please do not leave comment about this blog post not being useful to you, if you knew the answer. Few days ago, I received DM asking What is an AdventureWorks database and why in all the examples I use that instead of any other database (e.g. Pubs or  Northwind)? As matter of fact, when I went back to my question list, which I have yet not answered, there were a few more variations of this same question. AdventureWorks is a Sample Database shipped with SQL Server and it can be downloaded from http://codeplex.com site. AdventureWorks has replaced Northwind and Pubs from the sample database in SQL Server 2005. The Microsoft team keeps updating the sample database as they release new versions. Here are some quick links: AdventureWorks SQL Server 2008 SR4 AdventureWorks 2008R2 November CTP AdventureWorks for SQL Azure (December CTP) AventureWorks for SQL Server 2005 SP2A SQL SERVER – 2008 – Download and Install Samples Database AdventureWorks 2005 – Detail Tutorial I have previously written few other articles on the same subject; you can find them easily here: [email protected] Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Four Tutorial for SQL Server 2012 New Features

  - by pinaldave

  One of the very common question I receive on my facebook is that if there is any tutorial for SQL Server 2012 new enhanced features and solutions. I see this demand a bit increasing as the SQL Server 2012 is more and more being adopted. Here is the list of four tutorial which is specifically created for SQL Server 2012 by Microsoft. Multidimensional Modeling (Adventure Works Tutorial) This tutorial teaches you how to develop and deploy an Analysis Services project that enables the employees of Adventure Works Cycles to analyze various aspects of their business. Tabular Modeling (Adventure Works Tutorial) This tutorial teaches you how to create a SQL Server 2012 Analysis Services tabular model that enable sales and marketing teams to easily analyze internet sales data in the AdventureWorksDW2012 data warehouse. You will build the tabular model in SQL Server Data Tools. Tutorials and Demos for Power View Create Power View reports and explore Power View features. View demos, videos, and tutorials that help you get started quickly with Power View and successfully build reports with interactive filters and visualizations such as bubble charts, tiles, and cards. Tutorial: Using the hierarchyid Data Type This tutorial is intended for users who are experienced with Transact-SQL, but are new to the hierarchyid data type. In this tutorial, you convert an existing table to a hierarchical structure, and you also create a new table to store and manage hierarchical data efficiently. Note: The description of the course is taken from original course description. You will need to install SQL Server 2012 AdventureWorks for all this tutorial. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

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• SQL SERVER – Retrieve SQL Server Installation Date Time

  - by pinaldave

  I have been asked this question number of times and my answer always have been – search online and you will find the answer. Every single time when someone has followed my answer – they have found accurate answer in first few clicks. However increasingly this question getting very popular so I have decided to answer this question here. I usually prefer to create my own T-SQL script but in today’s case, I have taken the script from web. I have seen this script at so many places I do not know who is original creator so not sure who should get credit for the same. Question: How to retrieve SQL Server Installation date? Answer: Run following query and it will give you date of SQL Server Installation. SELECT create_date FROM sys.server_principals WHERE sid = 0x010100000000000512000000 Question: I have installed SQL Server Evaluation version how do I know what is the expiry date for it? Answer: SQL Server evaluation period is for 180 days. The expiration date is always 180 days from the initial installation. Following query will give an expiration date of evaluation version. -- Evaluation Version Expire Date SELECT create_date AS InstallationDate, DATEADD(DD, 180, create_date) AS 'Expiry Date' FROM sys.server_principals WHERE sid = 0x010100000000000512000000 GO I believe there is a way to do the same using registry but I have not explored it personally. Now as I said earlier there are many different blog posts on this subject. Let me list a few which I really enjoyed to read personally as they shared few more insights over this subject. Retrieving SQL Server 2012 Evaluation Period Expiry Date How to find the Installation Date for an Evaluation Edition of SQL Server Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DateTime, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Download Whitepaper – SQL Server 2008 R2 Analysis Services Operations Guide

  - by pinaldave

  SQL Server Analysis Service (SSAS) has been always interesting subject for research. Analysis Services cubes are a very powerful tool in the hands of the business intelligence (BI) developer. They provide an easy way to expose even large data models directly to business users. Microsoft has published very informative white paper on Analysis Services Operations Guide. This white paper is authored by Thomas Kejser, John Sirmon, and Denny Lee. In this guide you will find information on how to test and run Microsoft SQL Server Analysis Services in SQL Server 2005, SQL Server 2008, and SQL Server 2008 R2 in a production environment. The focus of this guide is how you can test, monitor, diagnose, and remove production issues on even the largest scaled cubes. This paper also provides guidance on how to configure the server for best possible performance. It is the goal of this guide to make your operations processes as painless as possible, and to have you run with the best possible performance without any additional development effort to your deployed cubes. In this guide, you will learn how to get the best out of your existing data model by making changes transparent to the data model and by making configuration changes that improve the user experience of the cube. Download SQL Server 2008 R2 Analysis Services Operations Guide Note: Abstract taken white paper. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, SQLAuthority News, T SQL, Technology

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• SQL SERVER – Puzzle Involving NULL – Resolve – Error – Operand data type void type is invalid for sum operator

  - by pinaldave

  Today is Monday let us start this week with interesting puzzle. Yesterday I had also posted quick question here: SQL SERVER – T-SQL Scripts to Find Maximum between Two Numbers Run following code: SELECT SUM(data) FROM (SELECT NULL AS DATA) t It will throw following error. Msg 8117, Level 16, State 1, Line 1 Operand data type void type is invalid for sum operator. I can easily fix if I use ISNULL Function as displayed following. SELECT SUM(data) FROM (SELECT ISNULL(NULL,0) AS DATA) t Above script will not throw an error. However, there is one more method how this can be fixed. Can you come up with another method which will not generate error? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQL SERVER – How to Recover SQL Database Data Deleted by Accident

  - by Pinal Dave

  In Repair a SQL Server database using a transaction log explorer, I showed how to use ApexSQL Log, a SQL Server transaction log viewer, to recover a SQL Server database after a disaster. In this blog, I’ll show you how to use another SQL Server disaster recovery tool from ApexSQL in a situation when data is accidentally deleted. You can download ApexSQL Recover here, install, and play along. With a good SQL Server disaster recovery strategy, data recovery is not a problem. You have a reliable full database backup with valid data, a full database backup and subsequent differential database backups, or a full database backup and a chain of transaction log backups. But not all situations are ideal. Here we’ll address some sub-optimal scenarios, where you can still successfully recover data. If you have only a full database backup This is the least optimal SQL Server disaster recovery strategy, as it doesn’t ensure minimal data loss. For example, data was deleted on Wednesday. Your last full database backup was created on Sunday, three days before the records were deleted. By using the full database backup created on Sunday, you will be able to recover SQL database records that existed in the table on Sunday. If there were any records inserted into the table on Monday or Tuesday, they will be lost forever. The same goes for records modified in this period. This method will not bring back modified records, only the old records that existed on Sunday. If you restore this full database backup, all your changes (intentional and accidental) will be lost and the database will be reverted to the state it had on Sunday. What you have to do is compare the records that were in the table on Sunday to the records on Wednesday, create a synchronization script, and execute it against the Wednesday database. If you have a full database backup followed by differential database backups Let’s say the situation is the same as in the example above, only you create a differential database backup every night. Use the full database backup created on Sunday, and the last differential database backup (created on Tuesday). In this scenario, you will lose only the data inserted and updated after the differential backup created on Tuesday. If you have a full database backup and a chain of transaction log backups This is the SQL Server disaster recovery strategy that provides minimal data loss. With a full chain of transaction logs, you can recover the SQL database to an exact point in time. To provide optimal results, you have to know exactly when the records were deleted, because restoring to a later point will not bring back the records. This method requires restoring the full database backup first. If you have any differential log backup created after the last full database backup, restore the most recent one. Then, restore transaction log backups, one by one, it the order they were created starting with the first created after the restored differential database backup. Now, the table will be in the state before the records were deleted. You have to identify the deleted records, script them and run the script against the original database. Although this method is reliable, it is time-consuming and requires a lot of space on disk. How to easily recover deleted records? The following solution enables you to recover SQL database records even if you have no full or differential database backups and no transaction log backups. To understand how ApexSQL Recover works, I’ll explain what happens when table data is deleted. Table data is stored in data pages. When you delete table records, they are not immediately deleted from the data pages, but marked to be overwritten by new records. Such records are not shown as existing anymore, but ApexSQL Recover can read them and create undo script for them. How long will deleted records stay in the MDF file? It depends on many factors, as time passes it’s less likely that the records will not be overwritten. The more transactions occur after the deletion, the more chances the records will be overwritten and permanently lost. Therefore, it’s recommended to create a copy of the database MDF and LDF files immediately (if you cannot take your database offline until the issue is solved) and run ApexSQL Recover on them. Note that a full database backup will not help here, as the records marked for overwriting are not included in the backup. First, I’ll delete some records from the Person.EmailAddress table in the AdventureWorks database.   I can delete these records in SQL Server Management Studio, or execute a script such as DELETE FROM Person.EmailAddress WHERE BusinessEntityID BETWEEN 70 AND 80 Then, I’ll start ApexSQL Recover and select From DELETE operation in the Recovery tab.   In the Select the database to recover step, first select the SQL Server instance. If it’s not shown in the drop-down list, click the Server icon right to the Server drop-down list and browse for the SQL Server instance, or type the instance name manually. Specify the authentication type and select the database in the Database drop-down list.   In the next step, you’re prompted to add additional data sources. As this can be a tricky step, especially for new users, ApexSQL Recover offers help via the Help me decide option.   The Help me decide option guides you through a series of questions about the database transaction log and advises what files to add. If you know that you have no transaction log backups or detached transaction logs, or the online transaction log file has been truncated after the data was deleted, select No additional transaction logs are available. If you know that you have transaction log backups that contain the delete transactions you want to recover, click Add transaction logs. The online transaction log is listed and selected automatically.   Click Add if to add transaction log backups. It would be best if you have a full transaction log chain, as explained above. The next step for this option is to specify the time range.   Selecting a small time range for the time of deletion will create the recovery script just for the accidentally deleted records. A wide time range might script the records deleted on purpose, and you don’t want that. If needed, you can check the script generated and manually remove such records. After that, for all data sources options, the next step is to select the tables. Be careful here, if you deleted some data from other tables on purpose, and don’t want to recover them, don’t select all tables, as ApexSQL Recover will create the INSERT script for them too.   The next step offers two options: to create a recovery script that will insert the deleted records back into the Person.EmailAddress table, or to create a new database, create the Person.EmailAddress table in it, and insert the deleted records. I’ll select the first one.   The recovery process is completed and 11 records are found and scripted, as expected.   To see the script, click View script. ApexSQL Recover has its own script editor, where you can review, modify, and execute the recovery script. The insert into statements look like: INSERT INTO Person.EmailAddress( BusinessEntityID, EmailAddressID, EmailAddress, rowguid, ModifiedDate) VALUES( 70, 70, N'[email protected]' COLLATE SQL_Latin1_General_CP1_CI_AS, 'd62c5b4e-c91f-403f-b630-7b7e0fda70ce', '20030109 00:00:00.000' ); To execute the script, click Execute in the menu.   If you want to check whether the records are really back, execute SELECT * FROM Person.EmailAddress WHERE BusinessEntityID BETWEEN 70 AND 80 As shown, ApexSQL Recover recovers SQL database data after accidental deletes even without the database backup that contains the deleted data and relevant transaction log backups. ApexSQL Recover reads the deleted data from the database data file, so this method can be used even for databases in the Simple recovery model. Besides recovering SQL database records from a DELETE statement, ApexSQL Recover can help when the records are lost due to a DROP TABLE, or TRUNCATE statement, as well as repair a corrupted MDF file that cannot be attached to as SQL Server instance. You can find more information about how to recover SQL database lost data and repair a SQL Server database on ApexSQL Solution center. There are solutions for various situations when data needs to be recovered. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• SQL SERVER – OVER clause with FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 – ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING

  - by pinaldave

  Yesterday I had discussed two analytical functions FIRST_VALUE and LAST_VALUE. After reading the blog post I received very interesting question. “Don’t you think there is bug in your first example where FIRST_VALUE is remain same but the LAST_VALUE is changing every line. I think the LAST_VALUE should be the highest value in the windows or set of result.” I find this question very interesting because this is very commonly made mistake. No there is no bug in the code. I think what we need is a bit more explanation. Let me attempt that first. Before you do that I suggest you read yesterday’s blog post as this question is related to that blog post. Now let’s have fun following query: USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, FIRST_VALUE(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID) FstValue, LAST_VALUE(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID) LstValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO The above query will give us the following result: As per the reader’s question the value of the LAST_VALUE function should be always 114 and not increasing as the rows are increased. Let me re-write the above code once again with bit extra T-SQL Syntax. Please pay special attention to the ROW clause which I have added in the above syntax. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, FIRST_VALUE(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) FstValue, LAST_VALUE(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) LstValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO Now once again check the result of the above query. The result of both the query is same because in OVER clause the default ROWS selection is always UNBOUNDED PRECEDING AND CURRENT ROW. If you want the maximum value of the windows with OVER clause you need to change the syntax to UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING for ROW clause. Now run following query and pay special attention to ROW clause again. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, FIRST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) FstValue, LAST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) LstValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO Here is the resultset of the above query which is what questioner was asking. So in simple word, there is no bug but there is additional syntax needed to add to get your desired answer. The same logic also applies to PARTITION BY clause when used. Here is quick example of how we can further partition the query by SalesOrderDetailID with this new functions. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, FIRST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) FstValue, LAST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) LstValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO Above query will give us windowed resultset on SalesOrderDetailsID as well give us FIRST and LAST value for the windowed resultset. There are lots to discuss for this two functions and we have just explored tip of the iceberg. In future post I will discover it further deep. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – DATE and TIME in SQL Server 2008

  - by pinaldave

  I was thinking about DATE and TIME datatypes in SQL Server 2008. I earlier wrote about the about best practices of the same. Recently I had written one of the script written for SQL Server 2008 had to run on SQL Server 2005 (don’t ask me why!), I had to convert the DATE and TIME datatypes to DATETIME. Let me run quick demo for the same. DECLARE @varDate AS DATE DECLARE @varTime AS TIME SET @varDate = '10/10/2010' SET @varTime = '12:12:12' SELECT CAST(@varDate AS DATETIME) C_Date SELECT CAST(@varTime AS DATETIME) C_Time As seen in example when DATE is converted to DATETIME it adds the of midnight. When TIME is converted to DATETIME it adds the date of 1900 and it is something one wants to consider if you are going to run script from SQL Server 2008 to earlier version with CONVERT. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: SQL, SQL Authority, SQL DateTime, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Download Whitepaper Using SharePoint List Data in PowerPivot

  - by pinaldave

  One of the many features of Microsoft SQL Server PowerPivot is the range of data sources that can be used to import data. Anything, from Microsoft SQL Server relational databases, Oracle databases, and Microsoft Access databases, to text documents, can be used as data sources in PowerPivot. In this paper, I explain one of the new and upcoming data sources that people are excited about – SharePoint list data in the form of Atom feeds. This white paper goes on to explain the different ways you can import SharePoint list data into PowerPivot, what types of lists are supported, various components that need to be installed to use this feature, and where to get those components. Download and read this whitepaper. Note: Abstract is taken from MSDN Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, SQLAuthority News, T SQL, Technology

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• SQL SERVER – Watch Online and Download – Inside of Next Generation SQL Server – Best Practices Analyzer using Microsoft Baseline Configuration Analyzer

  - by pinaldave

  I presented on subject Inside of Next Generation SQL Server – Denali online at Zeollar.com. This sessions are really fun as they are online, downloadable, and 100% demo oriented. I used SQL Server ‘Denali’ CTP 1 to present on the subject of What is New in Denali. My earlier session on the Topic of Best Practices Analyzer is also available to watch online here: SQL SERVER – Video – Best Practices Analyzer using Microsoft Baseline Configuration Analyzer I enjoyed presenting a lot on above two subjects. I would like to ask your opinion on the same. You can download the sessions and watch it yourself afterwords. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQLAuthority News – SQL Server Technical Article – The Data Loading Performance Guide

  - by pinaldave

  The white paper describes load strategies for achieving high-speed data modifications of a Microsoft SQL Server database. “Bulk Load Methods” and “Other Minimally Logged and Metadata Operations” provide an overview of two key and interrelated concepts for high-speed data loading: bulk loading and metadata operations. After this background knowledge, white paper describe how these methods can be [...]

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• SQLAuthority News – Hyderabad Techies February Fever Feb 11, 2010 – Indexing for Performance

  - by pinaldave

  I recently presented in Hyderabad User Group on the subject of The Other Side of SQL Server Index: Advanced Solutions to Ancient Problem , you can read more about this event here SQLAuthority News – MUGH – Microsoft User Group Hyderabad – Feb 2, 2010 Session Review. I really had great time talking about Index [...]

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• SQL SERVER – Learn SQL Server 2014 Online in a Day – My Latest Pluralsight Course

  - by Pinal Dave

  Click here watch SQL Server 2014 Administration New Features.  SQL Server 2014 was released earlier this year and it has been extremely popular in Microsoft world. Here is the announcement for everyone, who have been asking me to build a tutorial around SQL Server 2014. I have authored latest Pluralsight courses on the subject of SQL Server 2014. This course is 4 hours and 17 minutes long, but the best part is that this course contains all the latest features of SQL Server 2014. I have build this course with the assumption that DBA is familiar with earlier versions of SQL Server and wants to explore and learn new features of SQL Server 2014. The Challenge I Faced The biggest challenge I faced was how to come up with the outline for the course. The reason is that there are so many different features introduced in SQL Server 2014 that is will be difficult to cover each of the features in a single course. I wanted to cover the topics which are the most relevant and useful to developers, but in addition I also wanted to cover the topics which may be useful to develop if they know that they exists in the product. I finally decided to depend on blog readers and few of the SQL Experts. I reached out to selected 20 people via email and gave them a list of the topics which I should be covering in this course. They all work in different organizations and have a good understanding about the need of the DBA and Developers. Based on their feedback, I was able to come up with a very good outline which is currently very popular with Pluralsight library. Lots of people have asked me how was I able to come up with a course content outline so accurately. The credit for the same goes to the developers and DBA, who have voted in the topics and have helped me to build a very solid outline for the course. Outline of the Course Here is a quick outline for the course: Introduction Backup Enhancements Security Enhancements Columnstore Enhancements Online Data Operations Enhancements Enhancements with Microsoft Azure SSD Buffer Pool Extensions Resource Governor IO Miscellaneous Features Online Index Rebuilding Live Plans for Long Running Queries Transaction Durability Cardinality Estimation In Memory OLTP Optimization Well, I had a great fun working on the topics which I have mentioned in the outline. I am very confident that once you start with the course, you will indeed understand how each of the topics builds and presented. I have made sure that each of the topic has a vivid and clear story to begin with. I first explain the story and right after that I explain the concept. Who Should Attend This Course Everyone who has basic knowledge of SQL Server and wants to update themselves with SQL Server 2014. They should attend this course. One thing I have made sure that this course is easy to understand and I have decided complex subject into multiple parts. This way the learning is progressive and anyone with a poor knowledge of the subject can have enough time to understand the presented concept. Screenshot of the Course Here are few of the screenshot of the courses. How to Watch Video Course This course is available at Pluralsight, and you will need a valid login to Pluralsight. If you do not have Pluralsight login, you can quickly sign up for the FREE Trial. Click here watch SQL Server 2014 Administration New Features.  Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Video

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• SQLAuthority News – SafePeak’s SQL Server Performance Contest – Winners

  - by pinaldave

  SafePeak, the unique automated SQL performance acceleration and performance tuning software vendor, announced the winners of their SQL Performance Contest 2011. The contest quite unique: the writer of the best / most interesting and most community liked “performance story” would win an expensive gadget. The judges were the community DBAs that could participating and Like’ing stories and could also win expensive prizes. Robert Pearl SQL MVP, was the contest supervisor. I liked most of the stories and decided then to contact SafePeak and suggested to participate in the give-away and they have gladly accepted the same. The winner of best story is: Jason Brimhall (USA) with a story about a proc with a fair amount of business logic. Congratulations Jason! The 3 participants won the second prize of $100 gift card on amazon.com are: Michael Corey (USA), Hakim Ali (USA) and Alex Bernal (USA). And 5 participants won a printed copy of a book of mine (Book Reviews of SQL Wait Stats Joes 2 Pros: SQL Performance Tuning Techniques Using Wait Statistics, Types & Queues) are: Patrick Kansa (USA), Wagner Bianchi (USA), Riyas.V.K (India), Farzana Patwa (USA) and Wagner Crivelini (Brazil). The winners are welcome to send safepeak their mail address to receive the prizes (to “info ‘at’ safepeak.com”). Also SafePeak team asked me to welcome you all to continue sending stories, simply because they (and we all) like to read interesting stuff) as well as to send them ideas for future contests. You can do it from here: www.safepeak.com/SQL-Performance-Contest-2011/Submit-Story Congratulations to everybody! I found this very funny video about SafePeak: It looks like someone (maybe the vendor) played with video’s once and created this non-commercial like video: SafePeak dynamic caching is an immediate plug-n-play performance acceleration and scalability solution for cloud, hosted and business SQL server applications. By caching in memory result sets of queries and stored procedures, while keeping all those cache correct and up to date using unique patent pending technology, SafePeak can fix SQL performance problems and bottlenecks of most applications – most importantly: without actual code changes. By the way, I checked their website prior this contest announcement and noticed that they are running these days a special end year promotion giving between 30% to 45% discounts. Since the installation is quick and full testing can be done within couple of days – those have the need (performance problems) and have budget leftovers: I suggest you hurry. A free fully functional trial is here: www.safepeak.com/download, while those that want to start with a quote should ping here www.safepeak.com/quote. Good luck! Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Online Index Rebuilding Index Improvement in SQL Server 2012

  - by pinaldave

  Have you ever faced situation when you see something working and you feel it should not be working? Well, I had similar moments few days ago. I know that SQL Server 2008 supports online indexing. However, I also know that I cannot rebuild index ONLINE if I have used VARCHAR(MAX), NVARCHAR(MAX) or few other data types. While I held my belief very strongly I came across situation, where I had to go online and do little bit reading from Book Online. Here is the similar example. First of all – run following code in SQL Server 2008 or SQL Server 2008 R2. USE TempDB GO CREATE TABLE TestTable (ID INT, FirstCol NVARCHAR(10), SecondCol NVARCHAR(MAX)) GO CREATE CLUSTERED INDEX [IX_TestTable] ON TestTable (ID) GO CREATE NONCLUSTERED INDEX [IX_TestTable_Cols] ON TestTable (FirstCol) INCLUDE (SecondCol) GO USE [tempdb] GO ALTER INDEX [IX_TestTable_Cols] ON [dbo].[TestTable] REBUILD WITH (ONLINE = ON) GO DROP TABLE TestTable GO Now run the same code in SQL Server 2012 version. Observe the difference between both of the execution. You will be get following resultset. In SQL Server 2008/R2 it will throw following error: Msg 2725, Level 16, State 2, Line 1 An online operation cannot be performed for index ‘IX_TestTable_Cols’ because the index contains column ‘SecondCol’ of data type text, ntext, image, varchar(max), nvarchar(max), varbinary(max), xml, or large CLR type. For a non-clustered index, the column could be an include column of the index. For a clustered index, the column could be any column of the table. If DROP_EXISTING is used, the column could be part of a new or old index. The operation must be performed offline. In SQL Server 2012 it will run successfully and will not throw any error. Command(s) completed successfully. I always thought it will throw an error if there is VARCHAR(MAX) or NVARCHAR(MAX) used in table schema definition. When I saw this result it was clear to me that it will be for sure not bug enhancement in SQL Server 2012. For matter for the fact, I always wanted this feature to be added in SQL Server Engine as this will enable ONLINE Index Rebuilding for mission critical tables which needs to be always online. I quickly searched online and landed on Jacob Sebastian’s blog where he has blogged about it as well. Well, is there any other new feature in SQL Server 2012 which gave you good surprise? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – I am Presenting 2 Sessions at TechEd India

  - by pinaldave

  TechED is the event which I am always excited about. It is one of the largest technology in India. Microsoft Tech Ed India 2011 is the premier technical education and networking event for tech professionals interested in learning, connecting and exploring a broad set of current and soon-to-be released Microsoft technologies, tools, platforms and services. I am going to speak at the TechED on two very interesting and advanced subjects. Venue: The LaLiT Ashok Kumara Krupa High Grounds Bangalore – 560001, Karnataka, India Sessions Date: March 25, 2011 Understanding SQL Server Behavioral Pattern – SQL Server Extended Events Date and Time: March 25, 2011 12:00 PM to 01:00 PM History repeats itself! SQL Server 2008 has introduced a very powerful, yet very minimal reoccurring feature called Extended Events. This advanced session will teach experienced administrators’ capabilities that were not possible before. From T-SQL error to CPU bottleneck, error login to deadlocks –Extended Event can detect it for you. Understanding the pattern of events can prevent future mistakes. SQL Server Waits and Queues – Your Gateway to Perf. Troubleshooting Date and Time: March 25, 2011 04:15 PM to 05:15 PM Just like a horoscope, SQL Server Waits and Queues can reveal your past, explain your present and predict your future. SQL Server Performance Tuning uses the Waits and Queues as a proven method to identify the best opportunities to improve performance. A glance at Wait Types can tell where there is a bottleneck. Learn how to identify bottlenecks and potential resolutions in this fast paced, advanced performance tuning session. My session will be on the third day of the event and I am very sure that everybody will be in groove to learn new interesting subjects. I will have few give-away during and at the end of the session. I will not tell you what I will have but it will be for sure something you will love to have. Please make a point and reserve above time slots to attend my session. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology Tagged: SQL Extended Events

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