SAS 9.4 SQL Procedure User's Guide, Fourth Edition, 4th Edition

Chapter 1

Introduction to the SQL Procedure

What Is SQL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

What Is the SQL Procedure? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Null Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Comparing PROC SQL with the SAS DATA Step . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Notes about the Example Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

What Is SQL?

Structured Query Language (SQL) is a standardized, widely used language that retrieves

and updates data in relational tables and databases.

A relation is a mathematical concept that is similar to the mathematical concept of a set.

Relations are represented physically as two-dimensional tables that are arranged in rows

and columns. Relational theory was developed by E. F. Codd, an IBM researcher, and

first implemented at IBM in a prototype called System R. This prototype evolved into

commercial IBM products based on SQL. The Structured Query Language is now in the

public domain and is part of many vendors' products.

What Is the SQL Procedure?

The SQL procedure is the Base SAS implementation of Structured Query Language.

PROC SQL is part of Base SAS software, and you can use it with any SAS data set

(table). Often, PROC SQL can be an alternative to other SAS procedures or the DATA

step. You can use SAS language elements such as global statements, data set options,

functions, informats, and formats with PROC SQL just as you can with other SAS

procedures. PROC SQL enables you to perform the following tasks:

• generate reports

• generate summary statistics

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