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• SQL SERVER – 2012 – Summary of All the Analytic Functions – MSDN and SQLAuthority

  - by pinaldave

  SQL Server 2012 (RC0 Available here) has introduced new analytic functions. These functions were long awaited and I am glad that they are here. Previously when any of this function was needed people use to write long T-SQL code to simulate that and now no need of the same. Having available native function also helps performance as well readability. In last few days I have written many articles on this subject on my blog. The goal was make these complex analytic functions easy to understand and make it widely accepted. As this new functions are available and as awareness spreads we should start using the new functions. Here is the quick list of the new function and relevant MSDN site. Function SQLAuthority MSDN CUME_DIST CUME_DIST CUME_DIST FIRST_VALUE FIRST_VALUE FIRST_VALUE LAST_VALUE LAST_VALUE LAST_VALUE LEAD LEAD LEAD LAG LAG LAG PERCENTILE_CONT PERCENTILE_CONT PERCENTILE_CONT PERCENTILE_DISC PERCENTILE_DISC PERCENTILE_DISC PERCENT_RANK PERCENT_RANK PERCENT_RANK I also enjoyed three different puzzles during the course of this series which gave clear idea to the SQL Server 2012 analytic functions. SQL SERVER – Puzzle to Win Print Book – Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY SQL SERVER – Puzzle to Win Print Book – Write T-SQL Self Join Without Using LEAD and LAG SQL SERVER – Puzzle to Win Print Book – Explain Value of PERCENTILE_CONT() Using Simple Example This series will be always my dear series as during this series I had went through very unique experience of my book going out of stock and becoming available after 48 hours. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Cleaning Up SQL Server Indexes – Defragmentation, Fillfactor – Video

  - by pinaldave

  Storing data non-contiguously on disk is known as fragmentation. Before learning to eliminate fragmentation, you should have a clear understanding of the types of fragmentation. When records are stored non-contiguously inside the page, then it is called internal fragmentation. When on disk, the physical storage of pages and extents is not contiguous. We can get both types of fragmentation using the DMV: sys.dm_db_index_physical_stats. Here is the generic advice for reducing the fragmentation. If avg_fragmentation_in_percent > 5% and < 30%, then use ALTER INDEX REORGANIZE: This statement is replacement for DBCC INDEXDEFRAG to reorder the leaf level pages of the index in a logical order. As this is an online operation, the index is available while the statement is running. If avg_fragmentation_in_percent > 30%, then use ALTER INDEX REBUILD: This is replacement for DBCC DBREINDEX to rebuild the index online or offline. In such case, we can also use the drop and re-create index method.(Ref: MSDN) Here is quick video which covers many of the above mentioned topics. While Vinod and I were planning about Indexing course, we had plenty of fun and learning. We often recording few of our statement and just left it aside. Afterwords we thought it will be really funny Here is funny video shot by Vinod and Myself on the same subject: Here is the link to the SQL Server Performance:  Indexing Basics. Here is the additional reading material on the same subject: SQL SERVER – Fragmentation – Detect Fragmentation and Eliminate Fragmentation SQL SERVER – 2005 – Display Fragmentation Information of Data and Indexes of Database Table SQL SERVER – De-fragmentation of Database at Operating System to Improve Performance Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video

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• SQL SERVER – Download Free eBook – Introducing Microsoft SQL Server 2012

  - by pinaldave

  Database Administration and Business Intelligence is indeed very key area of the SQL Server. My very good friend Ross Mistry and Stacia Misner has recently wrote book which is for SQL Server 2012. The best part of the book is it is totally FREE! Well, this book assumes that you have certain level of SQL Server Administration as well Business Intelligence understanding. So if you are absolutely beginner I suggest you read other books of Ross as well attend Pluralsight course of Stacia Misner. Personally I read this book in last 10 days and I find it very easy to read and very comprehensive as well. Part I Database Administration (by Ross Mistry) 1. SQL Server 2012 Editions and Engine Enhancements 2. High-Availability and Disaster-Recovery Enhancements 3. Performance and Scalability 4. Security Enhancements 5. Programmability and Beyond-Relational Enhancements Part II Business Intelligence Development (by Stacia Misner) 6. Integration Services 7. Data Quality Services 8. Master Data Services 9. Analysis Services and PowerPivot 10. Reporting Services Here are various versions of the eBook. PDF ePub Mobi Amazon Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Removing Leading Zeros From Column in Table

  - by pinaldave

  Some questions surprises me and make me write code which I have never explored before. Today was similar experience as well. I have always received the question regarding how to reserve leading zeroes in SQL Server while displaying them on the SSMS or another application. I have written articles on this subject over here. SQL SERVER – Pad Ride Side of Number with 0 – Fixed Width Number Display SQL SERVER – UDF – Pad Ride Side of Number with 0 – Fixed Width Number Display SQL SERVER – Preserve Leading Zero While Coping to Excel from SSMS Today I received a very different question where the user wanted to remove leading zero and white space. I am using the same sample sent by user in this example. USE tempdb GO -- Create sample table CREATE TABLE Table1 (Col1 VARCHAR(100)) INSERT INTO Table1 (Col1) SELECT '0001' UNION ALL SELECT '000100' UNION ALL SELECT '100100' UNION ALL SELECT '000 0001' UNION ALL SELECT '00.001' UNION ALL SELECT '01.001' GO -- Original data SELECT * FROM Table1 GO -- Remove leading zeros SELECT SUBSTRING(Col1, PATINDEX('%[^0 ]%', Col1 + ' '), LEN(Col1)) FROM Table1 GO -- Clean up DROP TABLE Table1 GO Here is the resultset of above script. It will remove any leading zero or space and will display the number accordingly. This problem is a very generic problem and I am confident there are alternate solutions to this problem as well. If you have an alternate solution or can suggest a sample data which does not satisfy the SUBSTRING solution proposed, I will be glad to include them in follow up blog post with due credit. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – 2008 – Unused Index Script – Download

  - by pinaldave

  Download Missing Index Script with Unused Index Script Performance Tuning is quite interesting and Index plays a vital role in it. A proper index can improve the performance and a bad index can hamper the performance. Here is the script from my script bank which I use to identify unused indexes on any database. Please note, if you should not drop all the unused indexes this script suggest. This is just for guidance. You should not create more than 5-10 indexes per table. Additionally, this script sometime does not give accurate information so use your common sense. Any way, the scripts is good starting point. You should pay attention to User Scan, User Lookup and User Update when you are going to drop index. The generic understanding is if this values are all high and User Seek is low, the index needs tuning. The index drop script is also provided in the last column. Download Missing Index Script with Unused Index Script -- Unused Index Script -- Original Author: Pinal Dave (C) 2011 SELECT TOP 25 o.name AS ObjectName , i.name AS IndexName , i.index_id AS IndexID , dm_ius.user_seeks AS UserSeek , dm_ius.user_scans AS UserScans , dm_ius.user_lookups AS UserLookups , dm_ius.user_updates AS UserUpdates , p.TableRows , 'DROP INDEX ' + QUOTENAME(i.name) + ' ON ' + QUOTENAME(s.name) + '.' + QUOTENAME(OBJECT_NAME(dm_ius.OBJECT_ID)) AS 'drop statement' FROM sys.dm_db_index_usage_stats dm_ius INNER JOIN sys.indexes i ON i.index_id = dm_ius.index_id AND dm_ius.OBJECT_ID = i.OBJECT_ID INNER JOIN sys.objects o ON dm_ius.OBJECT_ID = o.OBJECT_ID INNER JOIN sys.schemas s ON o.schema_id = s.schema_id INNER JOIN (SELECT SUM(p.rows) TableRows, p.index_id, p.OBJECT_ID FROM sys.partitions p GROUP BY p.index_id, p.OBJECT_ID) p ON p.index_id = dm_ius.index_id AND dm_ius.OBJECT_ID = p.OBJECT_ID WHERE OBJECTPROPERTY(dm_ius.OBJECT_ID,'IsUserTable') = 1 AND dm_ius.database_id = DB_ID() AND i.type_desc = 'nonclustered' AND i.is_primary_key = 0 AND i.is_unique_constraint = 0 ORDER BY (dm_ius.user_seeks + dm_ius.user_scans + dm_ius.user_lookups) ASC GO Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Download, SQL Index, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Installing AdventureWorks Sample Database – SQL in Sixty Seconds #010 – Video

  - by pinaldave

  SQL Server has so many enhancements and features that quite often I feel like playing with various features and try out new things. I often come across situation where I want to try something new but I do not have sample data to experiment with. Also just like any sane developer I do not try any of my new experiments on production server. Additionally, when it is about new version of the SQL Server, there are cases when there is no relevant sample data even available on development server. In this kind of scenario sample database can be very much handy. Additionally, in many SQL Books and online blogs and articles there are scripts written by using AdventureWork database. The often receive request that where people can get sample database as well how to restore sample database. In this sixty seconds video we have discussed the same. You can get various resources used in this video from http://bit.ly/adw2012. More on Errors: SQL SERVER – Install Samples Database Adventure Works for SQL Server 2012 SQL SERVER – 2012 – All Download Links in Single Page – SQL Server 2012 SQLAuthority News – SQL Server 2012 – Microsoft Learning Training and Certification SQLAuthority News – Download Microsoft SQL Server 2012 RTM Now I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video

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• MySQL – Introduction to User Defined Variables

  - by Pinal Dave

  MySQL supports user defined variables to have some data that can be used later part of your query. You can save a value to a variable using a SELECT statement and later you can access its value. Unlike other RDBMSs, you do not need to declare the data type for a variable. The data type is automatically assumed when you assign a value. A value can be assigned to a variable using a SET command as shown below SET @server_type:='MySQL'; When you above command is executed, the value, MySQL is assigned to the variable called @server_type. Now you can use this variable in the later part of the code. Suppose if you want to display the value, you can use SELECT statement. SELECT @server_type; The result is MySQL. Once the value is assigned it remains for the entire session until changed by the later statements. So unlike SQL Server, you do not need to have this as part the execution code every time. (Because in SQL Server, the variables are execution scoped and dropped after the execution). You can give column name as below SELECT @server_type AS server_type; You can also SELECT statement to DECLARE and SELECT the values for a variable. SELECT @message:='Welcome to MySQL' AS MESSAGE; The result is Message -------- Welcome to MySQL You can make use of variables to effectively apply many logics. One of the useful method is to generate the row number as shown in this post MySQL – Generating Row Number for Each Row using Variable. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Tips and Tricks, T SQL

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• SQL SERVER – Contest Winner – What Next on SQL in Sixty Seconds – Poll Result

  - by Pinal Dave

  A few days ago, I have asked a question on this blog. The question was - What would you like to see in the next episodes of SQL in Sixty Seconds. The poll is still active and posted over here: SQL SERVER – Poll – What would you love to see in SQL in Sixty Seconds? The contest was to suggest the next item of SQL in Sixty Seconds and vote for the your choice of subject. There have been plenty of votes to this contest, however, there were only 4 comments to this blog post. Hence, selecting a winner was very simple. Result of Poll It is very clear from result, most of the people would like to watch Performance Tuning subjects. I will continue to build video on this subject in future. Contest Winner Now is the time for the winner of the contest, who left comments on the blog. The winner is Raelyard. Here is the comment which he has left on the blog. raelyard please reach out to me via email and I will send you the gift card. Current Contest Here is the contest which is currently running on this blog. You can take part in the contest and can win a Drone. SQL in Sixty Seconds Here are few of the episodes of SQL in Sixty Seconds, which you can watch. We will have more episodes of SQL in Sixty Seconds from next week which are focused on performance. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Video

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• SQL SERVER – 2011 – SEQUENCE is not IDENTITY

  - by pinaldave

  Yesterday I posted blog post on the subject SQL SERVER – 2011 – Introduction to SEQUENCE – Simple Example of SEQUENCE and I received comment where user was not clear about difference between SEQUENCE and IDENTITY. The reality is that SEQUENCE not like IDENTITY. There is very clear difference between them. Identity is about single column. Sequence is always incrementing and it is not dependent on any table. Here is the quick example of the same. USE AdventureWorks2008R2 GO CREATE SEQUENCE [Seq] AS [int] START WITH 1 INCREMENT BY 1 MAXVALUE 20000 GO -- Run five times SELECT NEXT VALUE FOR Seq AS SeqNumber; SELECT NEXT VALUE FOR Seq AS SeqNumber; SELECT NEXT VALUE FOR Seq AS SeqNumber; SELECT NEXT VALUE FOR Seq AS SeqNumber; SELECT NEXT VALUE FOR Seq AS SeqNumber; GO -- Clean Up DROP SEQUENCE [Seq] GO Here is the resultset. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Microsoft SQL Server 2014 CTP1 Product Guide

  - by Pinal Dave

  Today in User Group meeting there were lots of questions related to SQL Server 2014. There are plenty of people still using SQL Server 2005 but everybody is curious about what is coming in SQL Server 2014.  Microsoft has officially released SQL Server 2014 CTP1 Product Guide. You can easily download the product guide and explore various learning around SQL Server 2014 as well explore the new concepts introduced in this latest version. This SQL Server 2014 CTP1 Product Guide contains few interesting White Papers, a Datasheet and Presentation Deck. Here is the list of the white papers: Mission-Critical Performance and Scale with SQL Server and Windows Server Faster Insights from Any Data Platform for Hybrid Cloud SQL Server In-Memory OLTP Internals Overview for CTP1 SQL Server 2014 CTP1 Frequently Asked Questions for TechEd 2013 North America Here is the list of slide decks: SQL Server 2014 Level 100 Deck SQL Server 2014 Mission Critical Performance LEvel 300 Deck SQL Server 2014 Faster Insights from Any Data Level Level 300 Deck SQL Server 2014 Platform for Hybrid Cloud Level 100 Deck I have earlier downloaded the Product Guide and I have yet not completed reading everything SQL Server 2014 has to offer. If you want to read what are the features which I am going to use in SQL Server 2014, you can read over here. Download Microsoft SQL Server 2014 CTP1 Product Guide 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, T SQL, Technology

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• SQL SERVER – Download Microsoft SQL Server Compact 4.0 SP1

  - by pinaldave

  Microsoft SQL Server Compact 4.0 is a free, embedded database that software developers can use for building ASP.NET websites and Windows desktop applications. SQL Server Compact 4.0 is the default database for Microsoft WebMatrix. For enhanced development and debugging capabilities, including designer support, Visual Studio can be used to develop ASP.NET web applications and websites using SQL Server Compact 4.0. Enabled to work in the medium or partial trust environments in the web servers, and can be easily deployed along with the website to the third party website hosting service providers. SQL Server CE 4.0 also provides stronger data security with the use of the SHA2 encryption algorithms for encrypting the databases. Latest version also supports T-SQL syntax enhancement by adding support for OFFSET and FETCH that can be used to write paging queries. Used with ADO.NET Entity Framework, SQL Server Compact now supports the columns that have server generated keys like identity, rowguid etc. and the code-first programming model. SQL Server Compact 4.0 is freely redistributable under a redistribution license agreement. SQL Server Compact 3.5 and SQL Server Compact 4.0 can be installed and work side by side on a desktop. Download Microsoft SQL Server Compact 4.0 SP1 Here are my earlier article on SQL Server CE Difference Between SQL Server Compact Edition (CE) and SQL Server Express Edition SQL SERVER – CE – 3 Links to Performance Tuning Compact Edition SQL SERVER – CE – List of Information_Schema System Tables SQL SERVER – Server Side Paging in SQL Server CE (Compact Edition) SQL SERVER – CE – Samples Database for SQL CE 4.0 Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Find Details for Statistics of Whole Database – DMV – T-SQL Script

  - by pinaldave

  I was recently asked is there a single script which can provide all the necessary details about statistics for any database. This question made me write following script. I was initially planning to use sp_helpstats command but I remembered that this is marked to be deprecated in future. Again, using DMV is the right thing to do moving forward. I quickly wrote following script which gives a lot more information than sp_helpstats. USE AdventureWorks GO SELECT DISTINCT OBJECT_NAME(s.[object_id]) AS TableName, c.name AS ColumnName, s.name AS StatName, s.auto_created, s.user_created, s.no_recompute, s.[object_id], s.stats_id, sc.stats_column_id, sc.column_id, STATS_DATE(s.[object_id], s.stats_id) AS LastUpdated FROM sys.stats s JOIN sys.stats_columns sc ON sc.[object_id] = s.[object_id] AND sc.stats_id = s.stats_id JOIN sys.columns c ON c.[object_id] = sc.[object_id] AND c.column_id = sc.column_id JOIN sys.partitions par ON par.[object_id] = s.[object_id] JOIN sys.objects obj ON par.[object_id] = obj.[object_id] WHERE OBJECTPROPERTY(s.OBJECT_ID,'IsUserTable') = 1 AND (s.auto_created = 1 OR s.user_created = 1); If you have better script to retrieve information about statistics, please share here and I will publish it with due credit. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics, Statistics

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• SQL SERVER – 2000 – DBCC SQLPERF(waitstats) – Wait Type – Day 24 of 28

  - by pinaldave

  I have received many comments, email, suggestions and motivations for my current series of wait types and wait statistics. One of the questions which I keep on receiving almost every other day is whether all of the discussions I have presented so far are also applicable to SQL Server 2000. Additionally, I receive another question asking me if wait statistics matters in SQL Server 2000. If it is, then the asker wants to know how to measure wait types for SQL Server 2000. In SQL Server, you can run the following command to get a list of all the wait types: DBCC SQLPERF(waitstats) The query above will work in SQL Server 2005/2008/R2  because of backup compatibility. As you might have noticed, I have been discussing everything keeping SQL Server 2005+ in mind, but I have given little consideration on SQL Server 2000. However, I am pretty sure that most of the suggestions I have provided are applicable to SQL Server 2000. The wait types I have been discussing mostly exist in SQL Server 2000 as well. But the difference of the 2000 version is that it gets late recent releases, but it is worth it. Wait types are very essential to measure performance bottleneck. Because of this, I do not have to state that I am big fan of them just so I could identify performance bottleneck. Please read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Reducing Page Contention on TempDB

  - by pinaldave

  I have recently received following email. “We are using TraceFlag 1118 to reduce the tempDB contention on our servers (2000 and 2005). What is your opinion? We have read lots of material, would you please answer me in single line.” Wow, this was very interesting question. What intrigued me was the second last where I am asked to answer in a single line. There is something about this strong email, I feel like blogging it here. I think I can talk over this subject forever – well, there is no clear answer. There are so many caveats about everything.  Again, I must stay honest to the request about answering in single line. I also do not like to answer which is YES/NO. What should I do? Let me ask this question to community today? What will you answer to this email? Let me start this by answering it myself in one line and taking one side. “I enable this trace flag in SQL Server 2000 without hot patch or service pack and not in later versions (2005+) onwards as code is improved”. What do you do in this case? The best answer will feature in this blog with due credit. Regarding further read and hint here is Microsoft KB which I think is very helpful. In quick summary: (Read KB for accuracy) When any page is allocated first 8 pages are allocated in mixed extended. This trace flag allocates uniform extended at the time, reducing contention. You can enable this trace flag at startup. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL TempDB, TempDB

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• SQL SERVER – Capturing Wait Types and Wait Stats Information at Interval – Wait Type – Day 5 of 28

  - by pinaldave

  Earlier, I have tried to cover some important points about wait stats in detail. Here are some points that we had covered earlier. DMV related to wait stats reset when we reset SQL Server services DMV related to wait stats reset when we manually reset the wait types However, at times, there is a need of making this data persistent so that we can take a look at them later on. Sometimes, performance tuning experts do some modifications to the server and try to measure the wait stats at that point of time and after some duration. I use the following method to measure the wait stats over the time. -- Create Table CREATE TABLE [MyWaitStatTable]( [wait_type] [nvarchar](60) NOT NULL, [waiting_tasks_count] [bigint] NOT NULL, [wait_time_ms] [bigint] NOT NULL, [max_wait_time_ms] [bigint] NOT NULL, [signal_wait_time_ms] [bigint] NOT NULL, [CurrentDateTime] DATETIME NOT NULL, [Flag] INT ) GO -- Populate Table at Time 1 INSERT INTO MyWaitStatTable ([wait_type],[waiting_tasks_count],[wait_time_ms],[max_wait_time_ms],[signal_wait_time_ms], [CurrentDateTime],[Flag]) SELECT [wait_type],[waiting_tasks_count],[wait_time_ms],[max_wait_time_ms],[signal_wait_time_ms], GETDATE(), 1 FROM sys.dm_os_wait_stats GO ----- Desired Delay (for one hour) WAITFOR DELAY '01:00:00' -- Populate Table at Time 2 INSERT INTO MyWaitStatTable ([wait_type],[waiting_tasks_count],[wait_time_ms],[max_wait_time_ms],[signal_wait_time_ms], [CurrentDateTime],[Flag]) SELECT [wait_type],[waiting_tasks_count],[wait_time_ms],[max_wait_time_ms],[signal_wait_time_ms], GETDATE(), 2 FROM sys.dm_os_wait_stats GO -- Check the difference between Time 1 and Time 2 SELECT T1.wait_type, T1.wait_time_ms Original_WaitTime, T2.wait_time_ms LaterWaitTime, (T2.wait_time_ms - T1.wait_time_ms) DiffenceWaitTime FROM MyWaitStatTable T1 INNER JOIN MyWaitStatTable T2 ON T1.wait_type = T2.wait_type WHERE T2.wait_time_ms > T1.wait_time_ms AND T1.Flag = 1 AND T2.Flag = 2 ORDER BY DiffenceWaitTime DESC GO -- Clean up DROP TABLE MyWaitStatTable GO If you notice the script, I have used an additional column called flag. I use it to find out when I have captured the wait stats and then use it in my SELECT query to SELECT wait stats related to that time group. Many times, I select more than 5 or 6 different set of wait stats and I find this method very convenient to find the difference between wait stats. In a future blog post, we will talk about specific wait stats. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Get File Statistics Using fn_virtualfilestats

  - by pinaldave

  Quite often when I am staring at my SSMS I wonder what is going on under the hood in my SQL Server. I often want to know which database is very busy and which database is bit slow because of IO issue. Sometime, I think at the file level as well. I want to know which MDF or NDF is busiest and doing most of the work. Following query gets the same results very quickly. SELECT DB_NAME(vfs.DbId) DatabaseName, mf.name, mf.physical_name, vfs.BytesRead, vfs.BytesWritten, vfs.IoStallMS, vfs.IoStallReadMS, vfs.IoStallWriteMS, vfs.NumberReads, vfs.NumberWrites, (Size*8)/1024 Size_MB FROM ::fn_virtualfilestats(NULL,NULL) vfs INNER JOIN sys.master_files mf ON mf.database_id = vfs.DbId AND mf.FILE_ID = vfs.FileId GO When you run above query you will get many valuable information like what is the size of the file as well how many times the reads and writes are done for each file. It also displays the read/write data in bytes. Due to IO if there has been any stall (delay) in read or write, you can know that as well. I keep this handy but have not shared on blog earlier. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL View, T SQL, Technology Tagged: Statistics

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• SQL Authority News – Download SQL Server Data Type Conversion Chart

  - by pinaldave

  Datatypes are very important concepts of SQL Server and there are quite often need to convert them from one datatypes to another datatype. I have seen that deveoper often get confused when they have to convert the datatype. There are two important concept when it is about datatype conversion. Implicit Conversion: Implicit conversions are those conversions that occur without specifying either the CAST or CONVERT function. Explicit Conversions: Explicit conversions are those conversions that require the CAST or CONVERT function to be specified. What it means is that if you are trying to convert value from datetime2 to time or from tinyint to int, SQL Server will automatically convert (implicit conversation) for you. However, if you are attempting to convert timestamp to smalldatetime or datetime to int you will need to explicitely convert them using either CAST or CONVERT function as well appropriate parameters. Let us see a quick example of Implict Conversion and Explict Conversion. Implicit Conversion: Explicit Conversion: You can see from above example that how we need both of the types of conversion in different situation. There are so many different datatypes and it is humanly impossible to know which datatype require implicit and which require explicit conversion. Additionally there are cases when the conversion is not possible as well. Microsoft have published a chart where the grid displays various conversion possibilities as well a quick guide. Download SQL Server Data Type Conversion Chart Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – 2014 CTP1 Available for Download – SQL SERVER 2014 Community Technology Preview 1

  - by Pinal Dave

  Microsoft announced that SQL Server 2014 CTP 1 available to download at TechEd Europe. You can download SQL Server 2014 CTP1 from here. Additionally, there is in depth documentation of the product in the Product Guide over here. In this blog post I have in depth discussed what are the salient features which I was looking forward in the new version. Always On supports now 8 secondaries instead of 4 Online Indexing at partition level – this is a good thing as now index rebuilding can be done at a partition level Statistics at the partition level – this will be a huge improvement in performance In-Memory OLTP works by providing in-application memory storage for the most often used tables in SQL Server. Columnstore Index can be updated – I just can’t wait for this feature (Columnstore Index) Resource Governor can control IO along with CPU and Memory Increase performance by extending SQL Server in-memory buffer pool to SSDs Backup to Azure Storage You can read about the new features of the SQL Server 2014 in the following links: What’s New (Database Engine) What’s New in Analysis Services and Business Intelligence What’s New (Integration Services) What’s New (Replication) What’s New (Reporting Services) Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Service Pack, SQL Tips and Tricks, T SQL, Technology Tagged: CTP

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• SQL SERVER – Removing Leading Zeros From Column in Table – Part 2

  - by pinaldave

  Earlier I wrote a blog post about Remvoing Leading Zeros from Column In Table. It was a great co-incident that my friend Madhivanan (no need of introduction for him) also post a similar article over on BeyondRelational.com. I strongly suggest to read his blog as well as he has suggested some cool solutions to the same problem. On original blog post asked two questions 1) if my sample for testing is correct and 2) If there is any better method to achieve the same. The response was amazing. I am proud on our SQL Community that we all keep on improving on each other’s contribution. There are some really good suggestions as a comment. Let us go over them right now. Improving the ResultSet I had missed including all zeros in my sample set which was an overlook. Here is the new sample which includes all zero values as well. USE tempdb GO -- Create sample table CREATE TABLE Table1 (Col1 VARCHAR(100)) INSERT INTO Table1 (Col1) SELECT '0001' UNION ALL SELECT '000100' UNION ALL SELECT '100100' UNION ALL SELECT '000 0001' UNION ALL SELECT '00.001' UNION ALL SELECT '01.001' UNION ALL SELECT '0000' GO Now let us go over some of the fantastic solutions which we have received. Response from Rainmaker SELECT CASE PATINDEX('%[^0 ]%', Col1 + ' ‘') WHEN 0 THEN '' ELSE SUBSTRING(Col1, PATINDEX('%[^0 ]%', Col1 + ' '), LEN(Col1)) END FROM Table1 Response from Harsh Solution 1 SELECT SUBSTRING(Col1, PATINDEX('%[^0 ]%', Col1 + 'a'), LEN(Col1)) FROM Table1 Response from Harsh Solution 2 SELECT RIGHT(Col1, LEN(Col1)+1 -PATINDEX('%[^0 ]%', Col1 + 'a' )) FROM Table1 Response from lucazav SELECT T.Col1 , label = CAST( CAST(REPLACE(T.Col1, ' ', '') AS FLOAT) AS VARCHAR(10)) FROM Table1 AS T Response from iamAkashSingh SELECT REPLACE(LTRIM(REPLACE(col1,'0',' ')),' ','0') FROM table1 Here is the resultset of above scripts. It will remove any leading zero or space and will display the number accordingly. If you believe there is a better solution, please leave a comment. I am just glad to see so many various responses and all of them teach us something new. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Installing Data Quality Services (DQS) on SQL Server 2012

  - by pinaldave

  Data Quality Services is very interesting enhancements in SQL Server 2012. My friend and SQL Server Expert Govind Kanshi have written an excellent article on this subject earlier on his blog. Yesterday I stumbled upon his blog one more time and decided to experiment myself with DQS. I have basic understanding of DQS and MDS so I knew I need to start with DQS Client. However, when I tried to find DQS Client I was not able to find it under SQL Server 2012 installation. I quickly realized that I needed to separately install the DQS client. You will find the DQS installer under SQL Server 2012 >> Data Quality Services directory. The pre-requisite of DQS is Master Data Services (MDS) and IIS. If you have not installed IIS, you can follow the simple steps and install IIS in your machine. Once the pre-requisites are installed, click on MDS installer once again and it will install DQS just fine. Be patient with the installer as it can take a bit longer time if your machine is low on configurations. Once the installation is over you will be able to expand SQL Server 2012 >> Data Quality Services directory and you will notice that it will have a new item called Data Quality Client.  Click on it and it will open the client. Well, in future blog post we will go over more details about DQS and detailed practical examples. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology Tagged: Data Quality Services

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• SQL SERVER – Winners – Contest Win Joes 2 Pros Combo (USD 198)

  - by pinaldave

  Earlier this week we had contest ran over the blog where we are giving away USD 198 worth books of Joes 2 Pros. We had over 500+ responses during the five days of the contest. After removing duplicate and incorrect responses we had a total of 416 valid responses combined total 5 days. We got maximum correct answer on day 2 and minimum correct answer on day 5. Well, enough of the statistics. Let us go over the winners’ names. The winners have been selected randomly by one of the book editors of Joes 2 Pros. SQL Server Joes 2 Pros Learning Kit 5 Books Day 1 Winner USA: Philip Dacosta India: Sandeep Mittal Day 2 Winner USA: Michael Evans India: Satyanarayana Raju Pakalapati Day 3 Winner USA: Ratna Pulapaka India: Sandip Pani Day 4 Winner USA: Ramlal Raghavan India: Dattatrey Sindol Day 5 Winner USA: David Hall India: Mohit Garg I congratulate all the winners for their participation. All of you will receive emails from us. You will have to reply the email with your physical address. Once you receive an email please reply within 3 days so we can ship the 5 book kits to you immediately. Bonus Winners Additionally, I had announced that every day I will select a winner from the readers who have left comments with their favorite blog post. Here are the winners with their favorite blog post. Day 1: Prasanna kumar.D [Favorite Post] Day 2: Ganesh narim [Favorite Post] Day 3: Sreelekha [Favorite Post] Day 4: P.Anish Shenoy [Favorite Post] Day 5: Rikhil [Favorite Post] All the bonus winners will receive my print book SQL Wait Stats if your shipping address is in India or Pluralsight Subscription if you are outside India. If you are not winner of the contest but still want to learn SQL Server you can get the book from here. Amazon | 1 | 2 | 3 | 4 | 5 | Flipkart | Indiaplaza Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – A Puzzle – Fun with SEQUENCE in SQL Server 2012 – Guess the Next Value

  - by pinaldave

  Yesterday my friend Vinod Kumar wrote excellent blog post on SQL Server 2012: Using SEQUENCE. I personally enjoyed reading the content on this subject. While I was reading the blog post, I thought of very simple new puzzle. Let us see if we can try to solve it and learn a bit more about Sequence. Here is the script, which I executed. USE TempDB GO -- Create sequence CREATE SEQUENCE dbo.SequenceID AS BIGINT START WITH 3 INCREMENT BY 1 MINVALUE 1 MAXVALUE 5 CYCLE NO CACHE; GO -- Following will return 3 SELECT next value FOR dbo.SequenceID; -- Following will return 4 SELECT next value FOR dbo.SequenceID; -- Following will return 5 SELECT next value FOR dbo.SequenceID; -- Following will return which number SELECT next value FOR dbo.SequenceID; -- Clean up DROP SEQUENCE dbo.SequenceID; GO Above script gave me following resultset. 3 is the starting value and 5 is the maximum value. Once Sequence reaches to maximum value what happens? and WHY? Bonus question: If you use UNION between 2 SELECT statement which uses UNION, it also throws an error. What is the reason behind it? Can you attempt to answer this question without running this code in SQL Server 2012. I am very confident that irrespective of SQL Server version you are running you will have great learning. I will follow up of the answer in comments below. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – DATEDIFF – Accuracy of Various Dateparts

  - by pinaldave

  I recently received the following question through email and I found it very interesting so I want to share it with you. “Hi Pinal, In SQL statement below the time difference between two given dates is 3 sec, but when checked in terms of Min it says 1 Min (whereas the actual min is 0.05Min) SELECT DATEDIFF(MI,'2011-10-14 02:18:58' , '2011-10-14 02:19:01') AS MIN_DIFF Is this is a BUG in SQL Server ?” Answer is NO. It is not a bug; it is a feature that works like that. Let us understand that in a bit more detail. When you instruct SQL Server to find the time difference in minutes, it just looks at the minute section only and completely ignores hour, second, millisecond, etc. So in terms of difference in minutes, it is indeed 1. The following will also clear how DATEDIFF works: SELECT DATEDIFF(YEAR,'2011-12-31 23:59:59' , '2012-01-01 00:00:00') AS YEAR_DIFF The difference between the above dates is just 1 second, but in terms of year difference it shows 1. If you want to have accuracy in seconds, you need to use a different approach. In the first example, the accurate method is to find the number of seconds first and then divide it by 60 to convert it to minutes. SELECT DATEDIFF(second,'2011-10-14 02:18:58' , '2011-10-14 02:19:01')/60.0 AS MIN_DIFF Even though the concept is very simple it is always a good idea to refresh it. Please share your related experience with me through your comments. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DateTime, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – SQL Server Performance: Indexing Basics – SQL in Sixty Seconds #006 – Video

  - by pinaldave

  A DBA’s role is critical, because a production environment has to run 24×7, hence maintenance, trouble shooting, and quick resolutions are the need of the hour.  The first baby step into any performance tuning exercise in SQL Server involves creating, analyzing, and maintaining indexes. Though we have learnt indexing concepts from our college days, indexing implementation inside SQL Server can vary.  Understanding this behavior and designing our applications appropriately will make sure the application is performed to its highest potential. Vinod Kumar and myself we often thought about this and realized that practical understanding of the indexes is very important. One can not master every single aspects of the index. However there are some minimum expertise one should gain if performance is one of the concern. More on Indexes: SQL Index SQL Performance I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. Here is the interview of Vinod Kumar by myself. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Video

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• SQL SERVER – Determine if SSRS 2012 is Installed on your SQL Server

  - by Pinal Dave

  This example is from the Beginning SSRS by Kathi Kellenberger. Supporting files are available with a free download from the www.Joes2Pros.com web site. Determine if SSRS 2012 is Installed on your SQL Server You may already have SSRS, or you may need to install it. Before doing any installation it makes sense to know where you are now. If you happened to install SQL Server with all features, you have the tools you need. There are two tools you need: SQL Server Data Tools and Reporting Services installed in Native Mode. To find out if SQL Server Data Tools (SSDT) is installed, click the Start button, go to All Programs, and expand SQL Server 2012. Look for SQL Server Data Tools   Now, let’s check to see if SQL Server Reporting Services is installed. Click the Start > All Programs > SQL Server 2012 > Configuration Tools > SQL > Server Configuration Manager   Once Configuration Manager is running, select SQL Server Services. Look for SQL Server Reporting Services in the list of services installed. If you have both SQL Server Reporting Services service and SQL Server Developer tools installed, you will not have to install them again. You may have SQL Server installed, but are missing the Data Tools or the SSRS service or both. In tomorrow blog post we will go over how to install based on where you are now.   Tomorrow’s Post Tomorrow’s blog post will show how to install and configure SSRS. If you want to learn SSRS in easy to simple words – I strongly recommend you to get Beginning SSRS book from Joes 2 Pros. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Reporting Services, SSRS

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