It would be helpful to both communities if there was a factual
feature-by-feature grid comparing the relative capabilities of Postgresql
7.4 and MySQL 4.x. It would probably be best to limit it to objective
measures such as "Supports sub-selects in UPDATE queries". Even features
that are supported by both should be listed, just so the evaluator can
make it as a known issue. A separate supplemental section offering
subjective items such as scalability anecdotes would be useful, too.
An associate starting a project expecting to use MySQL asked me about it.
I had formed my own unscientific impressions that PostgreSQL was more
appropriate for his app, but I googled in vain for an updated PostgreSQL
vs. MySQL table as described above. I only found one from 2001, and many
of the distinctions no longer applied to current versions.