Mashable has published a list SQL TOOLBOX: 20+ Tools and Lessons About SQL

Here are the items that I found interesting and useful. (I had my MySql and Microsoft Sql filter on, so I didn’t bother to look at anything Oracle related.)

25 SQL Commandments - These hints–many of them previously unpublished–can help you avoid the plague of poorly written SQL statements
This is a useful list of reminders and ideas to help you write the best performing SQL.

Comparison of different SQL implementations - Compares the SQL 2003 Standard, PostgrSQL 8.2.0, DB2 Express-C v. 9.1, MS Sql Server 2005, MySql 5.0.18, and Oracle 10g r2.

This should be very useful if you are trying to move a database between servers or trying to decide which database to use.

Instant SQL Formatter - Formats SQL for different Sql server implementations. Seems very useful. Especially if you are switching between databases.

MySql Cheat Sheet - Lists key MySql commands and syntax.

Sql on Rails - “Taking the VC out of MVC” - seems interesting, so mainly a note to myself to checkout later.