Archive of SQL Examples - Site provides basic SQL syntax as well as query optimisation tips for various database management systems (SQL Server, MySQL, Access, Paradox).
Archive of SQL examples - Free archive of source code examples for SQL programming for various database engines
JCC's SQL Standard Page - A source of information about SQL standards.
SQL Dumpster - Free SQL scripts for website and application developers.
The SQL Summit: Understanding SQL/XML and Information Retrieval - Portal site with information about databases, SQL/XML, XQuery, modeling, information retrieval, and web and grid data access. Includes articles, papers, and audio and video programs.
SQLinForm - A free web-based Java tool to format any SQL statement independent from their Database. It can also prepare SQL statements for Java, C#, VB, ASP.
UESQLC (Universal Embedded SQL Compiler) - An embedded SQL-92 precompiler for C++ and Java, designed to be extensible using SGML documents. [Open source, GPL]
W3 Schools' SQL Tutorial - Useful SQL language reference for beginners and experts alike
