DATABASE

SQL :: Basics:-
SQL Tutorial - w3shool
SQL Tutorial - Chuo-Han Lee
SQL Tutorial - James Hoffman
SQL Tutorial - firstsql.com
SQL Tutorial - BayCon Group™
SQL Tutorial - webdevelopernotes.com
SQL Tutorial - sql-tutorial.net
SQL Tutorial - FunctionX
SQL Tutorial - About.com
SQL Interactive Tutorial
SQL Fundamentals
Learn SQL Tutorial
SQL for Web Nerds
SQL in Simple English
SQL - Structured Query Language
Introduction to Structured Query Language
Interactive Online SQL Training
A Gentle Introduction to SQL
SQL Reference and Tutorial
SQL FAQs
SQL :: Advanced:-
Advanced Online SQL Training
XML Query Language (XQL)
SQL Reference Page
Steve Litt's SQL Troubleshooting Page
JCC's SQL Standard Page
PHP/SQL Tutorial
Oracle / SQL :-
Oracle/SQL Tutorial
PL/SQL Reference and Tutorial
Oracle: SQL*Plus Tutorial
MySQL :-
MySQL Tutorial - About.comm
MySQL Documentations
MySQL Presentations
PostgreSQL :-
PostgreSQL Notes
Practical PostgreSQL
PostgreSQL FAQs

Oracle:-
Client/Server Computing
Developing Client/Server Applications with Oracle
High-Performance Oracle Database Applications
Oracle8 Black Book
Oracle8 How-To
Oracle Database Construction Kit
Oracle Data Warehousing Unleashed
Oracle Performance Tuning and Optimization
Oracle Programming with Visual Basic
Oracle Unleashed
Special Edition Using Oracle Web Application Server 3
Teach Yourself Oracle 8 In 21 Days
Using Oracle8
Working with Oracle Cartridges

Oracle / SQL :-

Oracle/SQL Tutorial
PL/SQL Reference and Tutorial
Oracle: SQL*Plus Tutorial

General :-

Oracle PL/SQL CD Bookshelf
High-Performance Oracle Applications
Teach Yourself Oracle 8 In 21 Days
Using Oracle PL/SQL
Using Oracle8
Oracle Unleashed
Oracle Performance Tuning and Optimization
Object Query Language (OQL)
XML Query Language (XQL)
Data Transfer Strategies (between XML and RDBMS)
A Gentle Introduction to SQL
Structured Query Language (SQL) : A Practical Introduction.
SQL for Web Nerds
Getting Started with SQL Server Books Online
Introduction to SQL
Teach Yourself SQL in 21 Days, 2nd Edition
Using Microsoft SQL Server 6.5
PostgreSQL Documentation
Practical PostgreSQL
PostgreSQL: Introduction and Concepts
PL/SQL Tutorial & Reference
Teach Yourself Transact-SQL in 21 Days
MySQL & mSQL
MySQL Reference Manual
An Introduction to MySQL
Building a Database-Driven Web Site Using PHP & MySQL
PHP & MySQL Tutorial
Programming the Perl DBI
Database Programming with Perl
Sybase SQL Server Unleashed
Sybase Stored Procedures for the World Wide Web
Sybase 101
Introduction to Sybase
Using Visual FoxPro 6
Teach Yourself Database Programming with Visual C++ 6 in 21 Days
Foundations of Object-Relational Mapping
Information Modeling
Introduction to Databases for the Web
Introduction to Databases for Web Developers
Getting Started with JDBC API
DB2 Application Development Guide
Getting Started with OLE DB
IBM DB2 Universal Database for UNIX
DB2 Java Stored Procedures by Examples
DB2 Cookbooks Download