PROC SQL: Beyond the Basics Using SAS®

6.2. Modifying Tables

An important element in PROC SQL is its Data Definition Language (DDL) capabilities. From creating and deleting tables (see Chapter 5, “Creating, Populating, and Deleting Tables”) and indexes to altering table structures and columns, the DDL provides PROC SQL programmers with a way to change (or redefine) the definition of one or more existing tables. The ALTER TABLE statement permits columns to be added, modified, or dropped in a table with the ADD, MODIFY, or DROP clauses. When a table’s columns or attributes are modified, the table’s structural dynamics also change. The following sections examine the various ways tables can be modified in the SQL procedure.

6.2.1. Adding New Columns

As requirements and needs change, ...