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• Using Substring() in XML FLOWR Queries

  Tonight I was monitoring the #sqlhelp hashtag on Twitter for a response to a question I asked when Randy Knight ( Twitter ) asked a question about using SUBSTRING in FLOWR statements with XML. #sqlhelp Is there a way to do a SQL Type "LIKE" Read More... Posted Monday, January 24, 2011 11:41 PM by Jonathan Kehayias | 1 Comments Filed under: Transact-SQL, Database Administration

• Learn Who Started that Trace with the Default Trace

  This is not Extended Event related but it came from a question on Twitter about how to tell who and from what machine a server side trace was created, and there is no way to explain this in 140 characters so here’s a blog post.  This information Read More... Posted Wednesday, December 29, 2010 3:00 PM by Jonathan Kehayias | 4 Comments Filed under: Transact-SQL, Database Administration

• Today’s Performance Tip: Views are for Convenience, Not Performance!

  I tweeted this last week on twitter and got a lot of retweets so I thought that I’d blog the story behind the tweet. Most vendor databases have views in them, and when people want to retrieve data from a database, it seems like the most common first stop Read More... Posted Monday, May 17, 2010 7:38 PM by Jonathan Kehayias | 2 Comments Filed under: Transact-SQL, Database Administration, Programming

• New Article on SQL Server Central: Using a Certificate Signed Stored Procedure to Execute sp_send_dbmail

  Part of the reason for a reduction in the amount of blogging that I have been doing is that I have tried to expand the amount of information that I put into writing up a topic and instead of blogging those topics, publish them as articles online.  Read More... Posted Thursday, December 17, 2009 3:58 AM by Jonathan Kehayias | 1 Comments Filed under: Transact-SQL, Database Administration, Security, Articles

• T-SQL Tuesday #001: Splitting Date/Time Ranges and Intersections

  At the end of November, Adam Machanic put out the invite to join a weekly blog party called TSQL Tuesday where bloggers have a given topic to blog about offering tips and tricks.  This weeks theme is Date/Time tricks so I thought I’d share a trick Read More... Posted Tuesday, December 08, 2009 3:17 PM by Jonathan Kehayias | 1 Comments Filed under: Transact-SQL, TSQL2sday

• The Scope of Transaction Isolation Levels

  This week a forums post had some incorrect information in it about the scope and effect of SET TRANSACTION ISOLATION LEVEL during query execution. I tried to politely correct the information, but I also thought I’d blog about it as well. The incorrect Read More... Posted Friday, November 20, 2009 3:21 PM by Jonathan Kehayias | 7 Comments Filed under: Transact-SQL

• Another use for the Default Trace: Mapping Temporary Tables to Sessions

  Here’s another use for the information captured by the default trace.  Ever wonder what session created the tables that exist in tempdb?  Well you can find it using the default trace and the sys.objects view in tempdb.  Any time an object Read More... Posted Tuesday, September 29, 2009 6:06 AM by Jonathan Kehayias | 3 Comments Filed under: Transact-SQL, Database Administration, Miscellaneous

• Digging into the SQL Plan Cache: Finding Missing Indexes

  This is one of those topics I planned to blog about a long time ago, but never actually got around to it, and consequently I keep having to hit search engines to find the code I provided in a forums post when I need to use it again. A while back, I helped Read More... Posted Monday, July 27, 2009 12:27 PM by Jonathan Kehayias | 5 Comments Filed under: Transact-SQL, Database Administration, Plan Cache

• Unexpected Side Effects? Problems from Implicit Conversions

  A coworker of mine brought me a problem that he found and was trying to understand. It took a few minutes, but the root of the problem being looked at was an implicit conversion. I am not exactly sure of what the use case was, or what the purpose of the Read More... Posted Thursday, July 16, 2009 10:58 PM by Jonathan Kehayias | 4 Comments Filed under: Transact-SQL

• Using DDL Triggers to Dynamically Create DML Triggers

  This one is from the MSDN Forums on a post titled DDL trigger limitations .  Basically the problem in a nutshell is that an application is harvesting information from the Internet and storing it in SQL Server on what appears to be a timed schedule.  Read More... Posted Thursday, May 28, 2009 7:24 AM by Jonathan Kehayias | 0 Comments Filed under: Transact-SQL, MSDN Forums, SQL Server 2008

• When was the last time a Database or file was shrunk?

  Just for starters, I don't need a primer on how shrinking a database is bad, or why I shouldn't be doing it. Trust me, I understand the implications of shrinking databases, why it shouldn't be done, and I explain this to people online all the time. That Read More... Posted Wednesday, May 13, 2009 1:52 PM by Jonathan Kehayias | 7 Comments Filed under: Transact-SQL

• What happens when you perform a rollback inside a trigger?

  A coworker who is studying for the MCTS exam for 2005 brought this question up and wanted help understanding why the answers in the study materials were correct.  After a few minutes of discussion, I decided this was one of those topics that was Read More... Posted Thursday, April 30, 2009 10:51 PM by Jonathan Kehayias | 1 Comments Filed under: Transact-SQL

• SQL Tip: Keep your Presentation Logic in your Presentation Layer

  Whether you are just starting out in SQL Server, or you have been working in SQL Server for many years, eventually in your work, you cross a boundary where someone will want data formatted in a different manner than it is stored in the database server. Read More... Posted Thursday, February 19, 2009 11:13 PM by Jonathan Kehayias | 1 Comments Filed under: Transact-SQL, MSDN Forums, Miscellaneous

• Drop All Indexes and Stats in one Script

  I am not sure why someone would want to do this, but it was asked on the forums, and I figured I would post the code I created to perform such a nightmarish operation.  As with any post that I make providing code that could be potentially damaging Read More... Posted Monday, December 15, 2008 8:44 AM by Jonathan Kehayias | 0 Comments Filed under: Transact-SQL, MSDN Forums

• The Anatomy of a Deadlock

  A common question of the forums is "How do I stop these deadlocks?" I wrote a small reference article on the SQL Examples Site for the forums for how to trap deadlocks using trace flags and Madhu Nair wrote an article for how to trap them with SQL Profiler: Read More... Posted Wednesday, July 30, 2008 1:50 PM by Jonathan Kehayias | 8 Comments Filed under: Transact-SQL, Database Administration, Deadlock