SQL Dialects Reference/References

Standards

 * SQL-86
 * SQL-89
 * SQL-92 — full text is available
 * SQL:1999 — can be purchased from ISO
 * SQL:2003 — can be purchased from ISO
 * working draft of SQL:2008, downloadable from Whitemarsh Information Systems Corporation.
 * SQL:2008 — can be purchased from ISO
 * SQL:2011 — can be purchased from ISO

Official product documentations

 * DB2 Version 9 Information Center
 * MonetDB documentation
 * SQLite documentation
 * Firebird / Interbase 6 language reference (ZIP archive, 8.9MB)
 * OpenLink Virtuoso Universal Server Documentation
 * Oracle Database 12g1 SQL Reference
 * Microsoft SQL Server Documentation
 * Linter SQL Server Documentation (English, old version);Linter SQL Server Documentation (Russian)
 * Oracle Database 12g1 SQL Reference
 * Microsoft SQL Server Documentation
 * Linter SQL Server Documentation (English, old version);Linter SQL Server Documentation (Russian)

Single implementation references and cheat sheets

 * Oracle PL/SQL Cheatsheet
 * Oracle XML Cheatsheet

Comparisons

 * Comparison of different SQL implementations
 * Comparison of Oracle, MySQL and PostgreSQL DBMS by Computing Division of Fermi National Accelerator Laboratory
 * SQL Function Reference: Oracle vs. SQL Server
 * SQL Functions — MySQL vs Oracle comparison by Eric Brian
 * Standard SQL - an article by Peter Gulutzan that compares SQL standards support in DB2, MSSQL and Oracle
 * Standard SQL - an article by Peter Gulutzan that compares SQL standards support in DB2, MSSQL and Oracle

Migration

 * Converting MySQL to PostgreSQL