SAS Certified Professional Prep Guide

Comparing SQL Joins and DATA Step Match-Merges

A Brief Overview

DATA step match-merges and PROC SQL joins can produce the same results. However, there are important differences between these two techniques. For example, a join does not require that you sort the data first; a DATA step match-merge requires that the data be sorted.

It is useful to compare the use of SQL joins and DATA step match-merges in the following situations:

• when all of the values of the selected variable match
• when only some of the values of the selected variable match

When All of the Values Match

When all of the values of the BY variable match, you can use a PROC SQL inner join to produce the same results as a DATA step match-merge.

Suppose you want ...