[From Lorenzo Alberton]
Handy quick reference sheets for Firebird SQL and PostgreSQL. Complete list of internal and UDF functions, a list of the native data types with their value ranges and limits, a reference of useful queries (including some queries against the System Tables and INFORMATION_SCHEMA).
The cheat sheet for Firebird 2 is available at this page:
http://www.alberton.info/firebird_cheat_sheet.html
The article continues at
http://www.alberton.info/postgresql_cheat_sheet.html