Browse by Tags

• Cursor vs Set
• Database theory
• Indexing
• Internals
• NULL
• Performance
• T-SQL

• Curious cursor optimization options

  The best way to optimize performance of a cursor is, of course, to rip it out and replace it with set-based logic. But there is still a small category of problems where a cursor will outperform a set-based solution. The introduction of ranking functions Read More... Posted Wednesday, November 21, 2007 2:15 AM by Hugo Kornelis | 13 Comments Filed under: Surprise, Performance, Cursor vs Set Attachment(s): Cursor comparison.xls

• What if null if null is null null null is null?

  In this fourth and final part in my series about NULL, I’ll discuss some well-known and some less well-known functions and keywords that are specifically created to deal with NULL values. And I will, of course, explain why null if null is null null null Read More... Posted Sunday, September 30, 2007 11:19 PM by Hugo Kornelis | 11 Comments Filed under: T-SQL, Surprise, Database theory, NULL

• The Beatles versus the Stones - the explanation

  On December 31 of last year, I posted this brain teaser , promising to post the answer “in a few days”. Apparently, 15 is a few J . In case you have forgotten what the puzzle was about and are too lazy to click the link above, the bottom line is that Read More... Posted Tuesday, January 16, 2007 10:44 PM by Hugo Kornelis | 0 Comments Filed under: T-SQL, Surprise, Internals, Indexing

• The Beatles versus the Stones

  Here’s a nice brain teaser, just before the end of the year. Despite the title, it is related to SQL Server, not to music! A common misconception amongst SQL Server users is that a clustered index on a table will ensure that data is returned in the order Read More... Posted Sunday, December 31, 2006 1:49 PM by Hugo Kornelis | 20 Comments Filed under: T-SQL, Surprise, Internals, Indexing

• The table scan from hell

  Greg Linwood, a fellow SQL Server MVP, has started a series of articles in which he attempts to prove that having a clustered index on each table is not a good practice. However, he has failed to include the effects of fragmentation into account, so I Read More... Posted Friday, November 03, 2006 7:55 PM by Hugo Kornelis | 10 Comments Filed under: Surprise, Internals, Performance, Indexing

• Fun with ambiguous table names

  Earlier today, I realised that Microsoft has forgotten to include some keywords in the list of reserved keywords. Now, a wise developer will still take care to omit those names when naming tables – but a bored developer can have loads of fun exploring Read More... Posted Saturday, September 02, 2006 9:24 PM by Hugo Kornelis | 1 Comments Filed under: T-SQL, Surprise