Proc SQL User's Guide.pdf

SAS ® 9.1 SQL Procedure

User’s Guide

The correct bibliographic citation for this manual is as follows: SAS Institute Inc., 2004.

SAS ® 9.1 SQL Procedure User’s Guide . Cary, NC: SAS Institute Inc.

SAS ® 9.1 SQL Procedure User’s Guide

ISBN 1-59047-334-5

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SAS Institute Inc., SAS Campus Drive, Cary, North Carolina 27513.

1st printing, January 2004

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Contents

Chapter 1 Introduction to the SQL Procedure 1

What Is SQL? 1

What Is the SQL Procedure? 1

Terminology 2

Comparing PROC SQL with the SAS DATA Step 3

Notes about the Example Tables 4

Chapter 2 Retrieving Data from a Single Table 11

Overview of the SELECT Statement 12

Selecting Columns in a Table 14

Creating New Columns 18

Sorting Data 25

Retrieving Rows That Satisfy a Condition 30

Summarizing Data 39

Grouping Data 45

Filtering Grouped Data 50

Validating a Query 52

Chapter 3 Retrieving Data from Multiple Tables 55

Introduction 56

Selecting Data from More Than One Table by Using Joins 56

Using Subqueries to Select Data 74

When to Use Joins and Subqueries 80

Combining Queries with Set Operators 81

Chapter 4 Creating and Updating Tables and Views 89

Introduction 90

Creating Tables 90

Inserting Rows into Tables 93

Updating Data Values in a Table 96

Deleting Rows 98

Altering Columns 99

Creating an Index 102

Deleting a Table 103

Using SQL Procedure Tables in SAS Software 103

Creating and Using Integrity Constraints in a Table 103

Creating and Using PROC SQL Views 105

Chapter 5 Programming with the SQL Procedure 111

Introduction 111

Using PROC SQL Options to Create and Debug Queries 112

Improving Query Performance 115

Accessing SAS System Information Using DICTIONARY Tables 117

Using PROC SQL with the SAS Macro Facility 120

Formatting PROC SQL Output Using the REPORT Procedure 127

Accessing a DBMS with SAS/ACCESS Software 128

Using the Output Delivery System (ODS) with PROC SQL 132

Chapter 6 Practical Problem-Solving with PROC SQL 133

Overview 134

Computing a Weighted Average 134

Comparing Tables 136

Overlaying Missing Data Values 138

Computing Percentages within Subtotals 140

Counting Duplicate Rows in a Table 141

Expanding Hierarchical Data in a Table 143

Summarizing Data in Multiple Columns 144

Creating a Summary Report 146

Creating a Customized Sort Order 148

Conditionally Updating a Table 150

Updating a Table with Values from Another Table 153

Creating and Using Macro Variables 154

Using PROC SQL Tables in Other SAS Procedures 157

Appendix 1 Recommended Reading 161

Recommended Reading 161

Glossary 163

Index 167

CHAPTER

Introduction to the SQL

Procedure

What Is SQL? 1

What Is the SQL Procedure? 1

Terminology 2

Tables 2

Queries 2

Null Values 3

Comparing PROC SQL with the SAS DATA Step 3

Notes about the Example Tables 4

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 rst 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 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 can

generate reports

generate summary statistics

retrieve data from tables or views

combine data from tables or views

create tables, views, and indexes

update the data values in PROC SQL tables

update and retrieve data from database management system (DBMS) tables

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