Sams Teach Yourself SQL in 24 Hours
- Table of Contents
- Copyright
- About the Authors
- Acknowledgments
- Tell Us What You Think!
- Introduction
- Part I: A SQL Concepts Overview
- Hour 1. Welcome to the World of SQL
- Part II: Building Your Database
- Hour 2. Defining Data Structures
- Hour 3. Managing Database Objects
- Hour 4. The Normalization Process
- Hour 5. Manipulating Data
- Hour 6. Managing Database Transactions
- Part III: Getting Effective Results from Queries
- Hour 7. Introduction to the Database Query
- Hour 8. Using Operators to Categorize Data
- Hour 9. Summarizing Data Results from a Query
- Hour 10. Sorting and Grouping Data
- Hour 11. Restructuring the Appearance of Data
- Hour 12. Understanding Dates and Times
- Part IV: Building Sophisticated Database Queries
- Hour 13. Joining Tables in Queries
- Hour 14. Using Subqueries to Define Unknown Data
- Hour 15. Combining Multiple Queries into One
- Single Queries Versus Compound Queries
- Why Would I Ever Want to Use a Compound Query?
- Compound Query Operators
- Using an ORDER BY with a Compound Query
- Using GROUP BY with a Compound Query
- Retrieving Accurate Data
- Summary
- Workshop
- Q&A
- Part V: SQL Performance Tuning
- Hour 16. Using Indexes to Improve Performance
- Hour 17. Improving Database Performance
- Part VI: Using SQL to Manage Users and Security
- Hour 18. Managing Database Users
- Hour 19. Managing Database Security
- Part VII: Summarized Data Structures
- Hour 20. Creating and Using Views and Synonyms
- Hour 21. Working with the System Catalog
- Part VIII: Applying SQL Fundamentals in Today's World
- Hour 22. Advanced SQL Topics
- Hour 23. Extending SQL to the Enterprise, the Internet, and the Intranet
- Hour 24. Extensions to Standard SQL
- Part IX: Appendixes
- Appendix A. Common SQL Commands
- Appendix B. Using MySQL for Exercises
- Appendix C. Answers to Quizzes and Exercises
- Appendix D. CREATE TABLE Statements for Book Examples
- Appendix E. INSERT Statements for Data in Book Examples
- Appendix F. Glossary
- Appendix G. Bonus Exercises
Why Would I Ever Want to Use a Compound Query?
Compound operators are used to combine and restrict the results of two SELECT statements. These operators can be used to return or suppress the output of duplicate records. Compound operators can bring together similar data that is stored in different fields.
Compound queries allow you to combine the results of more than one query to return a single set of data. Compound queries are often simpler to write than a single query with complex conditions. Compound queries also allow for more flexibility regarding the never-ending task of data retrieval.
Compound Query Operators | Next Section

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