I had a requirement to return the thread with the most replies in each forum at JavaRanch‘s Coderanch forums.  In Postgresql 8.4, this would be very easy – just use the window functions.  Unfortunately, we aren’t on Postgresql 8.4 yet.  The other common pattern is something like This doesn’t work well for me either because [...]

I went to a bank yesterday to inquire why I was receiving mail at my old address despite having moved a number of months ago.  The first thing the representative did was pull up my record to show me that my address was correct in their system.  While that’s very nice, the mail has their [...]

When people ask me how to learn to use a database or how to write SQL queries, I tell them to pick a database system and immerse themselves in it. In fact that advice goes for a lot of software technologies: just immerse yourself in a language, as programming tutorials are easy to come by [...]