Database development

Java

.NET

Software development

Web development

XML

Free DBMSs

IBM DB2 Express-C

SQL Server 2005 Express Edition

MySQL

Oracle 10g Express Edition (XE)

Free database tools

SQuirreL (JDBC based)

SQLyog - MySQL

Oracle

Oracle Application Express (HTML DB)

Oracle SQL Developer

Toad for Oracle

MySQL

Java driver

docs 4.1, 5.0, 5.1

Microsoft SQL Server

Management Studio Express

Microsoft SQL Server Database Publishing Wizard 1.1 - included in VisualStudio 2008 - tutorial

Java driver

Microsoft T-SQL

MSDN - TSQL reference

DevGuru TSQL charts

DevGuru TSQL quick reference