User's Guide
PART 1. Working with Databases
When you create a database, you normalize the data by placing information specific to different objects in different tables, rather than one large table with many redundant entries.
A join operation recreates a larger table using the information from two or more tables (or views). By using different joins, you can construct a variety of these virtual tables, each suited to a particular task.
This chapter assumes some knowledge of queries and the syntax of the select statement. Information about queries is located in Queries: Selecting Data from a Table. You may also wish to review the introductory material on joins, located in Joining Tables.
How joins work
How joins are structured
Key joins
Natural joins
Joins using comparisons
Inner, left-outer, and right-outer joins
Self-joins and correlation names
Cross joins
How joins are processed
Joining more than two tables
Joins involving derived tables
Transact-SQL outer joins