The Fifth Edition of Sams Teach Yourself SQL in 21 Days

More than 48,000 sold!

In just one hour a day, you’ll have all the skills you need to begin creating effective SQL queries, reports, and database applications. With this complete tutorial, you’ll quickly master the basics and then move on to more advanced features and concepts:

• Quickly apply essential SQL techniques in useful, real-world queries
• Design trustworthy, high-performance databases
• Manipulate your data with views and transactions
• Leverage powerful features including stored procedures, triggers, and cursors
• Work with new objects introduced with the latest SQL standards
• Get practical, expert tips on implementing SQL in your business environment

Learn on your own time, at your own pace

• No previous SQL or database experience required
• Learn techniques that work with any current version of SQL
• Discover how to write faster, more efficient queries
• Secure your data using best practices from experienced database administrators
• Build more powerful databases with features exclusive to Oracle SQL*Plus, Oracle PL/SQL, and Microsoft Transact-SQL
• Write queries for the free, open source MySQL database
• Embed your SQL code in other applications

Ryan Stephens and Ron Plew are President and VP of Perpetual Technologies, Inc. (PTI) in Indianapolis, IN, providing managed services and consulting for top database implementations running Oracle, SQL Server, and other leading technologies. They taught for 5+ years as adjunct professors at Indiana University-Purdue University. Their books include Sams Teach Yourself SQL in 24 Hours, First through Fourth Editions, Sams Teach Yourself SQL in 21 Days, Second through Fourth Editions, and Database Design.

Table of Contents

Introduction  1

PART I: Introducing SQL

LESSON 1: Getting Started with SQL     5

     A Brief History of SQL     5

     A Brief History of Databases     6

     Today’s Database Landscape     11

     A Cross-Product Language     12

         Early Implementations     12

         SQL and Client/Server Application Development     13

    An Overview of SQL     13

    Popular SQL Implementations     14

         MySQL     14

         Oracle     14

         Microsoft SQL Server and Sybase     15

         IBM DB2     16

    Open Database Connectivity     16

    Embedding SQL in Application Programming     17

LESSON 2: Introducing the Query     21

    Exploring SQL’s Background     21

    Learning Basic Query Syntax     22

    The Building Blocks of Data Retrieval: SELECT and FROM     23

    Applying Query Concepts     25

    Writing Your First Query     26

         Terminating a SQL Statement     28

         Selecting Individual Columns     28

         Changing the Order of the Columns     29

         Selecting Different Tables     31

    Selecting Distinct Values     31

         Exercises  37

LESSON 3: Expressions, Conditions, and Operators     39

    Working with Query Expressions     40

    Placing Conditions on Queries     40

    Learning How to Use Operators     42

        Arithmetic Operators     42

        Comparison Operators     55

        Character Operators     63

        Logical Operators     70

        Set Operators     75

        Miscellaneous Operators: IN and BETWEEN     78

LESSON 4: Clauses in SQL Queries     85

    Specifying Criteria with the WHERE Clause     87

    Order from Chaos: The ORDER BY Clause     89

    The GROUP BY Clause     98

    The HAVING Clause     105

    Combining Clauses     112

        Example 4.1     112

        Example 4.2     113

        Example 4.3     113

        Example 4.4     115

LESSON 5: Joining Tables     121

    Joining Multiple Tables in a Single SELECT Statement     121

        Cross Joining Tables     123

        Finding the Correct Column     128

    Joining Tables Based on Equality     129

    Joining Tables Based on Nonequality     137

    OUTER JOINs Versus INNER JOINs     139

    Joining a Table to Itself: The Self Join     143

LESSON 6: Embedding Subqueries into Queries     151

    Building a Subquery     153

    Using Aggregate Functions with Subqueries     160

    Nesting Subqueries     162

    Referencing Outside with Correlated Subqueries     166

    Using EXISTS, ANY, and ALL     169

LESSON 7: Molding Data with Built-in Functions     179

    Using Aggregate Functions to Summarize Data     180

         COUNT     180

         SUM     181

         AVG     182

         MAX     184

         MIN     185

         VARIANCE     186

         STDDEV     186

    Using Functions to Format Date and Time Values     187

         ADD_MONTHS/ADD_DATE     188

         LAST_DAY     190

         MONTHS_BETWEEN     191

         NEXT_DAY     193

         SYSDATE     193

    Using Functions for Arithmetic Operations     195

         ABS     195

         CEIL and FLOOR     196

         EXP 196

         LN and LOG     197

         MOD 198

         POWER     199

         SIGN 199

         SQRT     200

    Using Functions to Modify the Appearance of Character Values     201

         CHR     201

         CONCAT     202

         INITCAP     203

         LOWER and UPPER     203

 ...