SQL in 10 Minutes a Day, Sams Teach Yourself

Sams Teach Yourself SQL in 10 Minutes offers straightforward, practical answers when you need fast results.

By working through the book's 22 lessons of 10 minutes or less, you'll learn what you need to know to take advantage of the SQL language.

Lessons cover IBM DB2, Microsoft SQL Server and SQL Server Express, MariaDB, MySQL, Oracle and Oracle express, PostgreSQL, and SQLite.

Full-color code examples help you understand how SQL statements are structured Tips point out shortcuts and solutions Cautions help you avoid common pitfalls Notes explain additional concepts, and provide additional information

10 minutes is all you need to learn how to...

• Use the major SQL statements
• Construct complex SQL statements using multiple clauses and
• operators
• Retrieve, sort, and format database contents
• Pinpoint the data you need using a variety of filtering techniques
• Use aggregate functions to summarize data
• Join two or more related tables
• Insert, update, and delete data
• Create and alter database tables
• Work with views, stored procedures, and more

Auteur

Ben Forta is Adobe's Senior Director of Education Initiatives and has three decades of experience in the computer industry in product development, support, training, and product marketing. He is the author of the best-selling Sams Teach Yourself SQL in 10 Minutes (including spinoff titles on MariaDB, MySQL, SQL Server T-SQL, and Oracle PL/SQL), Learning Regular Expressions, as well as books on Java, Windows, and more. He has extensive experience in database design and development, has implemented databases for several highly successful commercial software programs and websites, and is a frequent lecturer and columnist on application development and Internet technologies. Ben lives in Oak Park, Michigan, with his wife, Marcy, and their children. He welcomes your email at ben@forta.com and invites you to visit his website at http://forta.com.

Contenu

Introduction 1 Who Is the Teach Yourself SQL Book For? . . . . . . . . . . . . . . . . . . . . . . . . . . 1 DBMSs Covered in This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Conventions Used in This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 Understanding SQL 5 Database Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 What Is SQL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Try It Yourself . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2 Retrieving Data 13 The SELECT Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Retrieving Individual Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Retrieving Multiple Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Retrieving All Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Retrieving Distinct Rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Limiting Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Using Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3 Sorting Retrieved Data 25 Sorting Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Sorting by Multiple Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Sorting by Column Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Specifying Sort Direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4 Filtering Data 33 Using the WHERE Clause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 The WHERE Clause Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5 Advanced Data Filtering 41 Combining WHERE Clauses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Using the IN Operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Using the NOT Operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 6 Using Wildcard Filtering 51 Using the LIKE Operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Tips for Using Wildcards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 7 Creating Calculated Fields 59 Understanding Calculated Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Concatenating Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Performing Mathematical Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 8 Using Data Manipulation Functions 69 Understanding Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Using Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 9 Summarizing Data 79 Using Aggregate Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Aggregates on Distinct Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Combining Aggregate Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 10 Grouping Data 89 Understanding Data Grouping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Creating Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Filtering Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Grouping and Sorting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 SELECT Clause Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …