Sidestepping the Pitfalls of IN and NULL

Posted by: on | Thursday, February 23, 2006     Comments

My colleague John recently blogged about the unexpected results of using the T-SQL IN operator on a set that contains NULL. Here is another solution to the problem.There are three main ways to test for existence in another table, listed here in order of increasing performance

  1. LEFT JOIN and look for NULLs in the right table
  2. Use the IN operator
  3. Use the EXISTS operator

In general, the EXISTS operator will generate the most efficient query plan, and it also isn't subject to the very NULL pitfall that plagues the IN operator. The query that John posted:

SELECT COUNT...

Software Development's Evolution towards Product Design

Posted by: on | Wednesday, February 22, 2006     Comments

Danc of Lost Garden has written many interesting and thought-provoking articles, mostly about game design. Today's article, however, is wider in scope, addressing the evolution of product design, and is well worth the read.

A search engine for code

Posted by: on | Saturday, February 18, 2006     Comments

Krugle is a search engine for source code that is supposed to make life easier for us developers. You can sign up for the Beta on their website and try it out sometime next month.  http://www.krugle.com/

Programmer's fonts

Posted by: on | Monday, February 06, 2006     Comments

Is Courier New just not doing it for you anymore? This page summarizes and rates different fixed-width fonts based on their suitability for use in a programming environment. The reviewer evaluates several factors including how easily the characters 'l', '1', and 'i' are distinguised, as well as the characters '0', 'o', and 'O'. After browsing several of the handy font previews, simply follow the associated link to download your new favorite programming font. The top-rated font, Bitstream Sans Vera Mono, looks great without ClearType and awful with it, so if you have font smoothing enabled, I recommend you look further ...