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• An XEvent a Day (10 of 31) – Targets Week – etw_classic_sync_target

  - by Jonathan Kehayias

  Yesterday’s post, Targets Week – pair_matching , looked at the pair_matching Target in Extended Events and how it could be used to find unmatched Events.  Today’s post will cover the etw_classic_sync_target Target, which can be used to track Events starting in SQL Server, out to the Windows Server OS Kernel, and then back to the Event completion in SQL Server. What is the etw_classic_sync_target Target? The etw_classic_sync_target Target is the target that hooks Extended Events in SQL Server...(read more)

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• An XEvent a Day (17 of 31) – A Look at Backup Internals and How to Track Backup and Restore Throughput (Part 1)

  - by Jonathan Kehayias

  Today’s post is a continuation of yesterday’s post How Many Checkpoints are Issued During a Full Backup? and the investigation of Database Engine Internals with Extended Events.  In today’s post we’ll look at how Backup’s work inside of SQL Server and how to track the throughput of Backup and Restore operations.  This post is not going to cover Backups in SQL Server as a topic; if that is what you are looking for see Paul Randal’s TechNet Article Understanding SQL Server Backups . Yesterday...(read more)

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• What’s new in SQL Prompt 6.3?

  - by Tom Crossman

  This post describes some of the improvements we’ve made in the latest version of SQL Prompt. Code suggestions In recent months, the focus of the SQL Prompt development team has been to remove annoyances and improve code suggestions. Here’s just a few of the improvements to code suggestions we’ve made in SQL Prompt 6.3: The suggestions box is no longer shown when there are no suggestions Suggestions are now shown if you continue to type a half-completed word More suggestions for new SQL Server 2014 syntax Improvements to partial match suggestions Improved suggestion ordering As well as improving suggestions, we’ve also added some new features. Select in Object Explorer You can now use SQL Prompt to select an object in the Object Explorer from a query window. This is useful because many SSMS features are available from an object’s Object Explorer context menu (eg select top 1000 rows, design, script as). To select an object in the Object Explorer, place the cursor over the object you want to select and press Ctrl + F12: Here’s a short video of the feature in action. $SELECTIONSTART$ and $SELECTIONEND$ placeholders You can now use $SELECTIONSTART$ and $SELECTIONEND$ placeholders in your snippet code. The code between these placeholders is selected when you insert the snippet. For example, the following snippet: $SELECTIONSTART$SELECT TOP 100 * FROM Table1$SELECTIONEND$ is inserted as: You can then press F5 to run the selected snippet code. For the full list of snippet placeholders you can use, see the documentation. Highlighting matching parentheses If your cursor is next to an opening or closing parenthesis in a query, SQL Prompt now automatically highlights the matching parenthesis: You can then use the SSMS and Visual Studio shortcut Ctrl + ] to move between parentheses. More improvements Those are just a few of the improvements in SQL Prompt 6.3. For the full list of features and bug fixes, see the release notes.

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• [Update] RedGate SQL Source Control and TFSPreview

  - by andyleonard

  31 Oct 2012 Update: SQL Source Control 3.1 is available! - Andy 12 Oct 2012 Update: The SQL Source Control 3.1 update is currently unavailable. I will provide additional updates when this version is re-released. - Andy I am excited that RedGate ’s SQL Source Control now supports connectivity to TFSPreview , Microsoft ’s cloud-based Application Life Cycle Management portal. Buck Woody ( Blog | @buckwoody ) and I have written about TFSPreview at SQLBlog already: Team Foundation Server (TFS) in the...(read more)

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• An XEvent a Day (22 of 31) – The Future – fn_dblog() No More? Tracking Transaction Log Activity in Denali

  - by Jonathan Kehayias

  I bet that made you look didn’t it?  Worry not, fn_dblog() still exists in SQL Server Denali, and I plan on using it to validate the information being returned by a new Event in SQL Server Denali CTP1, sqlerver.transaction_log, which brings with it the ability to correlate specific transaction log entries to the operations that actually caused them to occur. There is no greater source of information about the transaction log in SQL Server than Paul Randal’s blog category Transaction Log . ...(read more)

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• T-SQL Tuesday 24: Ode to Composable Code

  - by merrillaldrich

  I love the T-SQL Tuesday tradition, started by Adam Machanic and hosted this month by Brad Shulz . I am a little pressed for time this month, so today’s post is a short ode to how I love saving time with Composable Code in SQL. Composability is one of the very best features of SQL, but sometimes gets picked on due to both real and imaginary performance worries. I like to pick composable solutions when I can, while keeping the perf issues in mind, because they are just so handy and eliminate so much...(read more)

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• An XEvent a Day (28 of 31) – Tracking Page Compression Operations

  - by Jonathan Kehayias

  The Database Compression feature in SQL Server 2008 Enterprise Edition can provide some significant reductions in storage requirements for SQL Server databases, and in the right implementations and scenarios performance improvements as well.  There isn’t really a whole lot of information about the operations of database compression that is documented as being available in the DMV’s or SQL Trace.  Paul Randal pointed out on Twitter today that sys.dm_db_index_operational_stats() provides...(read more)

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• October 2012 Cumulative Updates are available - SQL Server 2008 R2 & SQL Server 2012

  - by AaronBertrand

  Microsoft released new cumulative updates for SQL Server; they announced them on their blog several hours ago . SQL Server 2012 RTM Cumulative Update # 4 KB Article: KB #2758687 25 fixes are listed at the time of publication Build number is 11.0.2383 Relevant for @@VERSION 11.0.2100 through 11.0.2382 SQL Server 2008 R2 Service Pack 1 Cumulative Update # 9 KB Article: KB #2756574 14 fixes are listed at the time of publication Build number is 10.50.2866 Relevant for @@VERSION 10.50.2500 through 10.50.2865...(read more)

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• Group SQL tables in SQL Server Management Studio object explorer

  - by MainMa

  I have a table which has approximately sixty tables, and other tables are added constantly. Each table is a part of a schema. A such quantity of tables makes it difficult to use Microsoft SQL Server Management Studio 2008. For example, I must scroll up in object explorer to access database related functions, or scroll down each time I need to access Views or Security features. Is it possible to group several tables to be able to expand or collapse them in Object Explorer? Maybe a folder may be displayed for each schema, letting collapse the folders I don't need to use?

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• Auto Increment feature of SQL Server

  - by Rahul Tripathi

  I have created a table named as ABC. It has three columns which are as follows:- The column number_pk (int) is the primary key of my table in which I have made the auto increment feature on for that column. Now I have deleted two rows from that table say Number_pk= 5 and Number_pk =6. The table which I get now is like this:- Now if I again enter two new rows in this table with the same value I get the two new Number_pk starting from 7 and 8 i.e, My question is that what is the logic behind this since I have deleted the two rows from the table. I know that a simple answer is because I have set the auto increment on for the primary key of my table. But I want to know is there any way that I can insert the two new entries starting from the last Number_pk without changing the design of my table? And how the SQL Server manage this record since I have deleted the rows from the database??

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• How do I filter one of the columns in a SQL Server SQL Query

  - by Kent S. Clarkson

  I have a table (that relates to a number of other tables) where I would like to filter ONE of the columns (RequesterID) - that column will be a combobox where only people that are not sales people should be selectable. Here is the "unfiltered" query, lets call it QUERY 1: SELECT RequestsID, RequesterID, ProductsID FROM dbo.Requests If using a separate query, lets call it QUERY 2, to filter RequesterID (which is a People related column, connected to People.PeopleID), it would look like this: SELECT People.PeopleID FROM People INNER JOIN Roles ON People.RolesID = Roles.RolesID INNER JOIN Requests ON People.PeopleID = Requests.RequesterID WHERE (Roles.Role <> N'SalesGuy') ORDER BY Requests.RequestsID Now, is there a way of "merging" the QUERY 2 into QUERY 1? (dbo.Requests in QUERY 1 has RequesterID populated as a Foreign Key from dbo.People, so no problem there... The connections are all right, just not know how to write the SQL query!)

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• SQL 2005 - Search stored procedures for text (Not all text is being searched)

  - by hamlin11

  The following bits of code do not seem to be searching the entire routine definition. Code block 1: select top 50 * from information_schema.routines where routine_definition like '%09/01/2008%' and specific_Name like '%NET' Code Block 2: SELECT ROUTINE_NAME, ROUTINE_DEFINITION FROM INFORMATION_SCHEMA.ROUTINES WHERE ROUTINE_DEFINITION LIKE '%EffectiveDate%' AND ROUTINE_TYPE='PROCEDURE' and ROUTINE_NAME like '%NET' I know for a fact that these bits of SQL work under most circumstances. The problem is this: When I run this for "EffectiveDate" which is buried at line ~800 in a few stored procedures, these stored procedures never show up in the results. It's as if "like" only searches so deep. Any tips on fixing this? I want to search the ENTIRE stored procedure for the specified text. Thanks!

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• How can we check that table have index or not ?

  - by kumar

  Hi, How can we check that table have index or not ? if have how to find that index for a particular column for a table? Regards, kumar

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• SQL Query for generating matrix like output querying related table in SQL Server

  - by Nagesh

  I have three tables: Product ProductID ProductName 1 Cycle 2 Scooter 3 Car Customer CustomerID CustomerName 101 Ronald 102 Michelle 103 Armstrong 104 Schmidt 105 Peterson Transactions TID ProductID CustomerID TranDate Amount 10001 1 101 01-Jan-11 25000.00 10002 2 101 02-Jan-11 98547.52 10003 1 102 03-Feb-11 15000.00 10004 3 102 07-Jan-11 36571.85 10005 2 105 09-Feb-11 82658.23 10006 2 104 10-Feb-11 54000.25 10007 3 103 20-Feb-11 80115.50 10008 3 104 22-Feb-11 45000.65 I have written a query to group the transactions like this: SELECT P.ProductName AS Product, C.CustName AS Customer, SUM(T.Amount) AS Amount FROM Transactions AS T INNER JOIN Product AS P ON T.ProductID = P.ProductID INNER JOIN Customer AS C ON T.CustomerID = C.CustomerID WHERE T.TranDate BETWEEN '2011-01-01' AND '2011-03-31' GROUP BY P.ProductName, C.CustName ORDER BY P.ProductName which gives the result like this: Product Customer Amount Car Armstrong 80115.50 Car Michelle 36571.85 Car Schmidt 45000.65 Cycle Michelle 15000.00 Cycle Ronald 25000.00 Scooter Peterson 82658.23 Scooter Ronald 98547.52 Scooter Schmidt 54000.25 I need result of query in MATRIX form like this: Customer |------------ Amounts --------------- Name |Car Cycle Scooter Totals Armstrong 80115.50 0.00 0.00 80115.50 Michelle 36571.85 15000.00 0.00 51571.85 Ronald 0.00 25000.00 98547.52 123547.52 Peterson 0.00 0.00 82658.23 82658.23 Schmidt 45000.65 0.00 54000.25 99000.90 Please help me to acheive the above result in SQL Server 2005. Using mulitple views or even temporory tables is fine for me.

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• Idera SQL Doctor 3.0 and MS SQL Changes

  New features worth mentioning in SQL doctor 3.0 begin with a new server dashboard that not only gives a comprehensive overview of a SQL Server instance's current health, but also several key details to help database administrators. Some of the details include recommendations on how to optimize server configuration, how to fix certain security issues, and how to get rid of performance bottlenecks. The latest version of SQL doctor also supplies users with key server information. The status of system parameters known to affect SQL Server performance, such as processes, disk partitions, cache, m...

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• Scripting a database copy from MS Sql 2005 to 2008 without detach/backup/RDP

  - by James Santiago

  My goal is to move a single SQL 2005 database to a seperate 2008 server. The issue is my level of access to both servers. On each I can only access the database and nothing else. I cant create a backup file or detach the database because I don't have access to the file system or to create a proxy. I've tried using the generate script function of sql 2005 management studio express to restore the schema but receive command not supported errors when attempting to execute the sql on the new database. Similarly I tried using EMS SQL Manager 2005 Lite to script a backup of the schema and data but ran into similar problems. How do I go about acomplishing this? I can't seem to find any solutions outside of using the detach and backup functions.

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• Validate a string in a table in SQL Server - CLR function or T-SQL

  - by Ashish Gupta

  I need to check If a column value (string) in SQL server table starts with a small letter and can only contain '_', '-', numbers and alphabets. I know I can use a SQL server CLR function for that. However, I am trying to implement that validation using a scalar UDF and could make very little here...I can use 'NOT LIKE', but I am not sure how to make sure I validate the string irrespective of the order of characters or in other words write a pattern in SQL for this. Am I better off using a SQL CLR function? Any help will be appreciated.. Thanks in advance Thank you everyone for their comments. This morning, I chose to go CLR function way. For the purpose of what I was trying to achieve, I created one CLR function which does the validation of an input string and have that called from a SQL UDF and It works well. Just to measure the performance of t-SQL UDF using SQL CLR function vs t- SQL UDF, I created a SQL CLR function which will just check if the input string contains only small letters, it should return true else false and have that called from a UDF (IsLowerCaseCLR). After that I also created a regular t-SQL UDF(IsLowerCaseTSQL) which does the same thing using the 'NOT LIKE'. Then I created a table (Person) with columns Name(varchar) and IsValid(bit) columns and populate that with names to test. Data :- 1000 records with 'Ashish' as value for Name column 1000 records with 'ashish' as value for Name column then I ran the following :- UPDATE Person Set IsValid=1 WHERE dbo.IsLowerCaseTSQL (Name) Above updated 1000 records (with Isvalid=1) and took less than a second. I deleted all the data in the table and repopulated the same with same data. Then updated the same table using Sql CLR UDF (with Isvalid=1) and this took 3 seconds! If update happens for 5000 records, regular UDF takes 0 seconds compared to CLR UDF which takes 16 seconds! I am very less knowledgeable on t-SQL regular expression or I could have tested my actual more complex validation criteria. But I just wanted to know, even I could have written that, would that have been faster than the SQL CLR function considering the example above. Are we using SQL CLR because we can implement we can implement lot richer logic which would have been difficult otherwise If we write in regular SQL. Sorry for this long post. I just want to know from the experts. Please feel free to ask if you could not understand anything here. Thank you again for your time.

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• Validate a string in a table in SQL Server - CLR function or T-SQL (Question updated)

  - by Ashish Gupta

  I need to check If a column value (string) in SQL server table starts with a small letter and can only contain '_', '-', numbers and alphabets. I know I can use a SQL server CLR function for that. However, I am trying to implement that validation using a scalar UDF and could make very little here...I can use 'NOT LIKE', but I am not sure how to make sure I validate the string irrespective of the order of characters or in other words write a pattern in SQL for this. Am I better off using a SQL CLR function? Any help will be appreciated.. Thanks in advance Thank you everyone for their comments. This morning, I chose to go CLR function way. For the purpose of what I was trying to achieve, I created one CLR function which does the validation of an input string and have that called from a SQL UDF and It works well. Just to measure the performance of t-SQL UDF using SQL CLR function vs t- SQL UDF, I created a SQL CLR function which will just check if the input string contains only small letters, it should return true else false and have that called from a UDF (IsLowerCaseCLR). After that I also created a regular t-SQL UDF(IsLowerCaseTSQL) which does the same thing using the 'NOT LIKE'. Then I created a table (Person) with columns Name(varchar) and IsValid(bit) columns and populate that with names to test. Data :- 1000 records with 'Ashish' as value for Name column 1000 records with 'ashish' as value for Name column then I ran the following :- UPDATE Person Set IsValid=1 WHERE dbo.IsLowerCaseTSQL (Name) Above updated 1000 records (with Isvalid=1) and took less than a second. I deleted all the data in the table and repopulated the same with same data. Then updated the same table using Sql CLR UDF (with Isvalid=1) and this took 3 seconds! If update happens for 5000 records, regular UDF takes 0 seconds compared to CLR UDF which takes 16 seconds! I am very less knowledgeable on t-SQL regular expression or I could have tested my actual more complex validation criteria. But I just wanted to know, even I could have written that, would that have been faster than the SQL CLR function considering the example above. Are we using SQL CLR because we can implement we can implement lot richer logic which would have been difficult otherwise If we write in regular SQL. Sorry for this long post. I just want to know from the experts. Please feel free to ask if you could not understand anything here. Thank you again for your time.

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• SQL Server and Hyper-V Dynamic Memory Part 3

  - by SQLOS Team

  In parts 1 and 2 of this series we looked at the basics of Hyper-V Dynamic Memory and SQL Server memory management. In this part Serdar looks at configuration guidelines for SQL Server memory management. Part 3: Configuration Guidelines for Hyper-V Dynamic Memory and SQL Server Now that we understand SQL Server Memory Management and Hyper-V Dynamic Memory basics, let’s take a look at general configuration guidelines in order to utilize benefits of Hyper-V Dynamic Memory in your SQL Server VMs. Requirements Host Operating System Requirements Hyper-V Dynamic Memory feature is introduced with Windows Server 2008 R2 SP1. Therefore in order to use Dynamic Memory for your virtual machines, you need to have Windows Server 2008 R2 SP1 or Microsoft Hyper-V Server 2008 R2 SP1 in your Hyper-V host. Guest Operating System Requirements In addition to this Dynamic Memory is only supported in Standard, Web, Enterprise and Datacenter editions of windows running inside VMs. Make sure that your VM is running one of these editions. For additional requirements on each operating system see “Dynamic Memory Configuration Guidelines” here. SQL Server Requirements All versions of SQL Server support Hyper-V Dynamic Memory. However, only certain editions of SQL Server are aware of dynamically changing system memory. To have a truly dynamic environment for your SQL Server VMs make sure that you are running one of the SQL Server editions listed below: ·         SQL Server 2005 Enterprise ·         SQL Server 2008 Enterprise / Datacenter Editions ·         SQL Server 2008 R2 Enterprise / Datacenter Editions Configuration guidelines for other versions of SQL Server are covered below in the FAQ section. Guidelines for configuring Dynamic Memory Parameters Here is how to configure Dynamic Memory for your SQL VMs in a nutshell: Hyper-V Dynamic Memory Parameter Recommendation Startup RAM 1 GB + SQL Min Server Memory Maximum RAM > SQL Max Server Memory Memory Buffer % 5 Memory Weight Based on performance needs   Startup RAM In order to ensure that your SQL Server VMs can start correctly, ensure that Startup RAM is higher than configured SQL Min Server Memory for your VMs. Otherwise SQL Server service will need to do paging in order to start since it will not be able to see enough memory during startup. Also note that Startup Memory will always be reserved for your VMs. This will guarantee a certain level of performance for your SQL Servers, however setting this too high will limit the consolidation benefits you’ll get out of your virtualization environment. Maximum RAM This one is obvious. If you’ve configured SQL Max Server Memory for your SQL Server, make sure that Dynamic Memory Maximum RAM configuration is higher than this value. Otherwise your SQL Server will not grow to memory values higher than the value configured for Dynamic Memory. Memory Buffer % Memory buffer configuration is used to provision file cache to virtual machines in order to improve performance. Due to the fact that SQL Server is managing its own buffer pool, Memory Buffer setting should be configured to the lowest value possible, 5%. Configuring a higher memory buffer will prevent low resource notifications from Windows Memory Manager and it will prevent reclaiming memory from SQL Server VMs. Memory Weight Memory weight configuration defines the importance of memory to a VM. Configure higher values for the VMs that have higher performance requirements. VMs with higher memory weight will have more memory under high memory pressure conditions on your host. Questions and Answers Q1 – Which SQL Server memory model is best for Dynamic Memory? The best SQL Server model for Dynamic Memory is “Locked Page Memory Model”. This memory model ensures that SQL Server memory is never paged out and it’s also adaptive to dynamically changing memory in the system. This will be extremely useful when Dynamic Memory is attempting to remove memory from SQL Server VMs ensuring no SQL Server memory is paged out. You can find instructions on configuring “Locked Page Memory Model” for your SQL Servers here. Q2 – What about other SQL Server Editions, how should I configure Dynamic Memory for them? Other editions of SQL Server do not adapt to dynamically changing environments. They will determine how much memory they should allocate during startup and don’t change this value afterwards. Therefore make sure that you configure a higher startup memory for your VM because that will be all the memory that SQL Server utilize Tune Maximum Memory and Memory Buffer based on the other workloads running on the system. If there are no other workloads consider using Static Memory for these editions. Q3 – What if I have multiple SQL Server instances in a VM? Having multiple SQL Server instances in a VM is not a general recommendation for predictable performance, manageability and isolation. In order to achieve a predictable behavior make sure that you configure SQL Min Server Memory and SQL Max Server Memory for each instance in the VM. And make sure that: ·         Dynamic Memory Startup Memory is greater than the sum of SQL Min Server Memory values for the instances in the VM ·         Dynamic Memory Maximum Memory is greater than the sum of SQL Max Server Memory values for the instances in the VM Q4 – I’m using Large Page Memory Model for my SQL Server. Can I still use Dynamic Memory? The short answer is no. SQL Server does not dynamically change its memory size when configured with Large Page Memory Model. In virtualized environments Hyper-V provides large page support by default. Most of the time, Large Page Memory Model doesn’t bring any benefits to a SQL Server if it’s running in virtualized environments. Q5 – How do I monitor SQL performance when I’m trying Dynamic Memory on my VMs? Use the performance counters below to monitor memory performance for SQL Server: Process - Working Set: This counter is available in the VM via process performance counters. It represents the actual amount of physical memory being used by SQL Server process in the VM. SQL Server – Buffer Cache Hit Ratio: This counter is available in the VM via SQL Server counters. This represents the paging being done by SQL Server. A rate of 90% or higher is desirable. Conclusion These blog posts are a quick start to a story that will be developing more in the near future. We’re still continuing our testing and investigations to provide more detailed configuration guidelines with example performance numbers with a white paper in the upcoming months. Now it’s time to give SQL Server and Hyper-V Dynamic Memory a try. Use this guidelines to kick-start your environment. See what you think about it and let us know of your experiences. - Serdar Sutay Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• Whether to use UNION or OR in SQL Server Queries

  - by Dinesh Asanka

  Recently I came across with an article on DB2 about using Union instead of OR. So I thought of carrying out a research on SQL Server on what scenarios UNION is optimal in and which scenarios OR would be best. I will analyze this with a few scenarios using samples taken  from the AdventureWorks database Sales.SalesOrderDetail table. Scenario 1: Selecting all columns So we are going to select all columns and you have a non-clustered index on the ProductID column. --Query 1 : OR SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 714 OR ProductID =709 OR ProductID =998 OR ProductID =875 OR ProductID =976 OR ProductID =874 --Query 2 : UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 714 UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 709 UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 998 UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 875 UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 976 UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 874 So query 1 is using OR and the later is using UNION. Let us analyze the execution plans for these queries. Query 1 Query 2 As expected Query 1 will use Clustered Index Scan but Query 2, uses all sorts of things. In this case, since it is using multiple CPUs you might have CX_PACKET waits as well. Let’s look at the profiler results for these two queries: CPU Reads Duration Row Counts OR 78 1252 389 3854 UNION 250 7495 660 3854 You can see from the above table the UNION query is not performing well as the  OR query though both are retuning same no of rows (3854).These results indicate that, for the above scenario UNION should be used. Scenario 2: Non-Clustered and Clustered Index Columns only --Query 1 : OR SELECT ProductID,SalesOrderID, SalesOrderDetailID FROM Sales.SalesOrderDetail WHERE ProductID = 714 OR ProductID =709 OR ProductID =998 OR ProductID =875 OR ProductID =976 OR ProductID =874 GO --Query 2 : UNION SELECT ProductID,SalesOrderID, SalesOrderDetailID FROM Sales.SalesOrderDetail WHERE ProductID = 714 UNION SELECT ProductID,SalesOrderID, SalesOrderDetailID FROM Sales.SalesOrderDetail WHERE ProductID = 709 UNION SELECT ProductID,SalesOrderID, SalesOrderDetailID FROM Sales.SalesOrderDetail WHERE ProductID = 998 UNION SELECT ProductID,SalesOrderID, SalesOrderDetailID FROM Sales.SalesOrderDetail WHERE ProductID = 875 UNION SELECT ProductID,SalesOrderID, SalesOrderDetailID FROM Sales.SalesOrderDetail WHERE ProductID = 976 UNION SELECT ProductID,SalesOrderID, SalesOrderDetailID FROM Sales.SalesOrderDetail WHERE ProductID = 874 GO So this time, we will be selecting only index columns, which means these queries will avoid a data page lookup. As in the previous case we will analyze the execution plans: Query 1 Query 2 Again, Query 2 is more complex than Query 1. Let us look at the profile analysis: CPU Reads Duration Row Counts OR 0 24 208 3854 UNION 0 38 193 3854 In this analyzis, there is only slight difference between OR and UNION. Scenario 3: Selecting all columns for different fields Up to now, we were using only one column (ProductID) in the where clause.  What if we have two columns for where clauses and let us assume both are covered by non-clustered indexes? --Query 1 : OR SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 714 OR CarrierTrackingNumber LIKE 'D0B8%' --Query 2 : UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 714 UNION SELECT * FROM Sales.SalesOrderDetail WHERE CarrierTrackingNumber  LIKE 'D0B8%' Query 1 Query 2: As we can see, the query plan for the second query has improved. Let us see the profiler results. CPU Reads Duration Row Counts OR 47 1278 443 1228 UNION 31 1334 400 1228 So in this case too, there is little difference between OR and UNION. Scenario 4: Selecting Clustered index columns for different fields Now let us go only with clustered indexes: --Query 1 : OR SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 714 OR CarrierTrackingNumber LIKE 'D0B8%' --Query 2 : UNION SELECT * FROM Sales.SalesOrderDetail WHERE ProductID = 714 UNION SELECT * FROM Sales.SalesOrderDetail WHERE CarrierTrackingNumber  LIKE 'D0B8%' Query 1 Query 2 Now both execution plans are almost identical except is an additional Stream Aggregate is used in the first query. This means UNION has advantage over OR in this scenario. Let us see profiler results for these queries again. CPU Reads Duration Row Counts OR 0 319 366 1228 UNION 0 50 193 1228 Now see the differences, in this scenario UNION has somewhat of an advantage over OR. Conclusion Using UNION or OR depends on the scenario you are faced with. So you need to do your analyzing before selecting the appropriate method. Also, above the four scenarios are not all an exhaustive list of scenarios, I selected those for the broad description purposes only.

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• How to join dynamic sql statement in variable with normal statement

  - by Oliver

  I have a quite complicated query which will by built up dynamically and is saved in a variable. As second part i have another normal query and i'd like to make an inner join between these both. To make it a little more easier here is a little example to illustrate my problem. For this little example i used the AdventureWorks database. Some query built up dynamically (Yes, i know here is nothing dynamic here, cause it's just an example.) DECLARE @query AS varchar(max) ; set @query = ' select HumanResources.Employee.EmployeeID ,HumanResources.Employee.LoginID ,HumanResources.Employee.Title ,HumanResources.EmployeeAddress.AddressID from HumanResources.Employee inner join HumanResources.EmployeeAddress on HumanResources.Employee.EmployeeID = HumanResources.EmployeeAddress.EmployeeID ;'; EXEC (@query); The normal query i have select Person.Address.AddressID ,Person.Address.City from Person.Address Maybe what i'd like to have but doesn't work select @query.* ,Addresses.City from @query as Employees inner join ( select Person.Address.AddressID ,Person.Address.City from Person.Address ) as Addresses on Employees.AddressID = Addresses.AddressID

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• sql 2008 metadata modified date

  - by Kumar

  Is there a way to identify the timestamp when an object(table/view/stored proc...) was modified ? there's a refdate in sysobjects but it's always the same as crdate atleast in my case and i know that alter view/alter table/alter proc commands have been run many times post creation

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• t-sql recursive query

  - by stackoverflowuser

  Based on an existing table I used CTE recursive query to come up with following data. But failing to apply it a level further. Data is as below id name parentid -------------------------- 1 project 0 2 structure 1 3 path_1 2 4 path_2 2 5 path_3 2 6 path_4 3 7 path_5 4 8 path_6 5 I want to recursively form full paths from the above data. Means the recursion will give the following output. FullPaths ------------- Project Project\Structure Project\Structure\Path_1 Project\Structure\Path_2 Project\Structure\Path_3 Project\Structure\Path_1\path_4 Project\Structure\Path_2\path_5 Project\Structure\Path_3\path_6 Thanks

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• Use SQL to filter the results of a stored procedure

  - by Ben McCormack

  I've looked at other questions on Stack Overflow related to this question, but none of them seemed to answer this question clearly. We have a system Stored Procedure called sp_who2 which returns a result set of information for all running processes on the server. I want to filter the data returned by the stored procedure; conceptually, I might do it like so: SELECT * FROM sp_who2 WHERE login='bmccormack' That method, though, doesn't work. What are good practices for achieving the goal of querying the returned data of a stored procedure, preferably without having to look of the code of the original stored procedure and modify it.

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• Stored Procedure To Search the AccessRights given to the Users.

  - by thevan

  Hi, I want to display the Access Rights given to the Users for the particular module. I have Seven Tables such as RoleAccess, Roles, Functions, Module, SubModule, Company and Unit. RoleAccess is the Main Table. The AccessRights given will be stored in the RoleAccess Table only. RoleAccess Table has the following columns such as RoleID, CompanyID, UnitID, FunctionID, ModuleID, SubModuleID, Create, Update, Delete, Read, Approve. Here Create_f, Update_f, Delete_f, Read_f and Approve_f are flags. Company Table has two columns such as CompanyID and CompanyName. Unit Table has three columns such as UnitID, UnitName and CompanyID. Roles Table has four columns such as RoleID, RoleName, CompanyID and UnitID. Module Table has two columns such as ModuleID and ModuleName. SubModule Table has three columns such as ModuleID, SubModuleID, SubModuleName. Functions Table has five columns such as FunctionID, FunctionName, ModuleID and SubModuleID. At First, The RoleAccess Table does not contain any records. So I want to display the ModuleName, SubModuleName, FunctionName, CompanyID, RoleID, UnitID, FunctionID, ModuleID, SubModuleID, Create_f, Update_f, Delete_f, Read_f and Approve_f. If the AccessRights is assigned to the Particular RoleID means the flags in the search results will be 1 else it will be 0. I have witten one stored procedure but it displays the records based on the RoleID stored in the RoleAccess table. But I also want to display the Flags as 0 for the Roles not stored in the RoleAccess Table. I want the Stored Procedure for this. Any one please help me.

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