SAS Certification Prep Guide, 4th Edition

Understanding Joins

Joins combine tables horizontally (side by side) by combining rows. The tables being joined are not required to have the same number of rows or columns.

Note: You can use a join to combine views as well as tables. Most of the following references to tables are also applicable to views; any exceptions are noted. In-line views are introduced later in this chapter. For more information about PROC SQL views, see Creating and Managing Views Using PROC SQL.

When you use a PROC SQL query to join tables, you must decide how you want the rows from the various tables to be combined. There are two main types of joins, as shown below.

Type of Join	Output
Inner join	Only the rows that match across all table(s)
Outer ...