The #1 Easy, Common-Sense Guide to SQL Queries-Updated with More Advanced Techniques and Solutions

Foreword by Keith W. Hare, Vice Chair, USA SQL Standards Committee

SQL Queries for Mere Mortals has earned worldwide praise as the clearest, simplest tutorial on writing effective queries with the latest SQL standards and database applications. Now, author John L. Viescas has updated this hands-on classic with even more advanced and valuable techniques.

Step by step, Viescas guides you through creating reliable queries for virtually any current SQL-based database. He demystifies all aspects of SQL query writing, from simple data selection and filtering to joining multiple tables and modifying sets of data.

Building on the basics, Viescas shows how to solve challenging real-world problems, including applying multiple complex conditions on one table, performing sophisticated logical evaluations, and using unlinked tables to think "outside the box."

In two brand-new chapters, you learn how to perform complex calculations on groups for sophisticated reporting, and how to partition data into windows for more flexible aggregation.

Practice all you want with downloadable sample databases for today's versions of Microsoft Office Access, Microsoft SQL Server, and the open source MySQL and PostgreSQL databases. Whether you're a DBA, developer, user, or student, there's no better way to master SQL.

Coverage includes:

• Getting started: understanding what relational databases are, and ensuring that your database structures are sound
• SQL basics: using SELECT statements, creating expressions, sorting information with ORDER BY, and filtering data using WHERE
• Summarizing and grouping data with GROUP BY and HAVING clauses
• Drawing data from multiple tables: using INNER JOIN, OUTER JOIN, and UNION operators, and working with subqueries
• Modifying data sets with UPDATE, INSERT, and DELETE statements
• Advanced queries: complex NOT and AND, conditions, if-then-else using CASE, unlinked tables, driver tables, and more
• NEW! Using advanced GROUP BY keywords to create subtotals, roll-ups, and more
• NEW! Applying window functions to answer more sophisticated questions, and gain deeper insight into your data

John L. Viescas is an independent database consultant with more than 50 years of experience. He began his career as a systems analyst, designing large database applications for IBM mainframe systems. He spent 6 years at Applied Data Research in Dallas, Texas, where he directed a staff of more than 30 people and was responsible for research, product development, and customer support of database products for IBM mainframe computers. While working at Applied Data Research, John completed a degree in business finance at the University of Texas at Dallas, graduating cum laude.

John joined Tandem Computers, Inc., in 1988, where he was responsible for the development and implementation of database marketing programs in Tandem's U.S. Western Sales region. He developed and delivered technical seminars on Tandem's relational database management system, NonStop SQL. John wrote his first book, A Quick Reference Guide to SQL (Microsoft Press, 1989), as a research project to document the similarities in the syntax among the ANSI-86 SQL standard, IBM's DB2, Microsoft's SQL Server, Oracle Corporation's Oracle, and Tandem's NonStop SQL. He wrote the first edition of Running Microsoft Access (Microsoft Press, 1992) while on sabbatical from Tandem. He has since written four editions of Running, three editions of Microsoft Office Access Inside Out (Microsoft Press, 2003, 2007, and 2010-the successor to the Running series), Building Microsoft Access Applications (Microsoft Press, 2005), and Effective SQL (Addison-Wesley, 2017).

John formed his own company in 1993. He provides information systems management consulting for a variety of small to large businesses around the world, with a specialty in the Microsoft Access and SQL Server database management products. He maintains offices in Nashua, New Hampshire, and Paris, France. He was recognized as a "Most Valuable Professional" (MVP) from 1993 to 2015 by Microsoft Product Support Services for his assistance with technical questions on public support forums. He set a landmark 20 consecutive years as an MVP in 2013.
You can visit John's Web site at www.viescas.com.

Foreword xxi
Preface xxii
Acknowledgments xxiv
About the Author xxv
Introduction 1
Are You a Mere Mortal? 1
About This Book 2
What This Book Is Not 4
How to Use This Book 4
Reading the Diagrams Used in This Book 5
Sample Databases Used in This Book 9
"Follow the Yellow Brick Road" 12

PART I: RELATIONAL DATABASES AND SQL 13
Chapter 1: What Is Relational? 15
Types of Databases 15
A Brief History of the Relational Model 16
In the Beginning . . . 16
Relational Database Systems 17
Anatomy of a Relational Database 19
Tables 20
Columns 21
Rows 21
Keys 22
Views 23
Relationships 25
What's in It for You? 29
Where Do You Go from Here? 30
Summary 31
Chapter 2: Ensuring Your Database Structure Is Sound 33
Why Is this Chapter Here? 34
Why Worry about Sound Structures? 34
Fine-Tuning Columns 35
What's in a Name? (Part One) 35
Smoothing Out the Rough Edges 38
Resolving Multipart Columns 40
Resolving Multivalued Columns 43
Fine-Tuning Tables 46
What's in a Name? (Part Two) 46
Ensuring a Sound Structure 48
Resolving Unnecessary Duplicate Columns 50
Identification Is the Key 56
Establishing Solid Relationships 60
Establishing a Deletion Rule 63
Setting the Type of Participation 64
Setting the Degree of Participation 66
Is That All? 69
Summary 69
Chapter 3: A Concise History of SQL 71
The Origins of SQL 72
Early Vendor Implementations 73
". . . And Then There Was a Standard" 75
Evolution of the ANSI/ISO Standard 76
Other SQL Standards 79
Commercial Implementations 83
What the Future Holds 83
Why Should You Learn SQL? 84
Which Version of SQL Does this Book Cover? 84
Summary 85

PART II: SQL BASICS 87
Chapter 4: Creating a Simple Query 89
Introducing SELECT 90
The SELECT Statement 91
A Quick Aside: Data versus Information 93
Translating Your Request into SQL 95
Expanding the Field of Vision 100
Using a Shortcut to Request All Columns 101
Eliminating Duplicate Rows 103
Sorting Information 105
First Things First: Collating Sequences 107
Let's Now Come to Order 108
Saving Your Work 111
Sample Statements 113
Summary 122
Problems for You to Solve 123
Chapter 5: Getting More Than Simple Columns 125
What Is an Expression? 126
What Type of Data Are You Trying to Express? 127
Changing Data Types: The CAST Function 130
Specifying Explicit Values 132
Character String Literals 133
Numeric Literals 135
Datetime Literals 135
Types of Expressions 138
Concatenation 138
Mathematical Expressions 142
Date and Time Arithmetic 146
Using Expressions in a SELECT Clause 150
Working with a Concatenation Expression 151
Naming the Expression 152
Working with a Mathematical Expression 154
Working with a Date Expression 156
A Brief Digression: Value Expressions 157
That "Nothing" Value: Null 159
Int…