PROC SQL: Beyond the Basics Using SAS®

6.5. Summary

1. Data Definition Language (DDL) statements provide programmers with a way to redefine the definition of one or more existing tables (see section 6.2).

2. As one or more new columns are added to a table, each is automatically added at the end of a table’s descriptor record (see section 6.2.1).

3. To add one or more columns in a designated order, the SQL standard provides a couple of choices to choose from (see section 6.2.2).

4. PROC SQL enables a character column (but not a numeric column) to have its length changed (see section 6.2.3).

5. A column’s format and label information can be modified with a MODIFY clause (see sections 6.2.4 and 6.2.5).

6. The RENAME= SAS data set option must be used in a FROM clause to rename column names (see section 6.2.6 ...