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About this Course

cap03.gif (979 bytes) This course is intended for serious computer hobbyists, IT students, and IT professionals.

The free online textbook for this course is Sams Teach Yourself SQL in 24 Hours, Third Edition. Read the Introduction.

offiste01.jpg (430 bytes) Indicates links that take you away from the Free-Ed.Net site. Use the links on these offsite pages carefully, and use the Back function on your browser to return to the assigments.

Join a Study Group

Learning experiences are always enhanced and enriched by interacting with others in the same "class." Now you can join a virtual classroom where you can share your experiences, answer questions, and find answers to your own questions.

Go to the SQL study group


Online Study Aids

Common SQL Commands

Lesson 15. Combining Multiple Queries into One

In this lesson you will learn about:

  • An overview of the operators used to combine queries
  • When to use the commands to combine queries
  • Using the GROUP BY with the compound operators
  • Using the ORDER BY with the compound operators
  • How to retrieve accurate data


The query operators covered in this hour are not currently supported by MySQL, as of the version 3.23. As of version 4.0, the UNION operator will be supported.

-- From the introduction to Hour 15 of your textbook

Reading Assignments

Read the following sections from your free online textbook:

offiste01.jpg (430 bytes) Single Queries Versus Compound Queries
offiste01.jpg (430 bytes) Why Would I Ever Want to Use a Compound Query?
offiste01.jpg (430 bytes) Compound Query Operators
offiste01.jpg (430 bytes) Using an ORDER BY with a Compound Query
offiste01.jpg (430 bytes) Using GROUP BY with a Compound Query
offiste01.jpg (430 bytes) Retrieving Accurate Data

Learning Activities

  1. Use this search box to refine and expand your understanding of new terms and concepts in the reading assignments.

Custom Search
  1. offiste01.jpg (430 bytes) Read theSummary  of the lesson.
  2. offiste01.jpg (430 bytes) Test your understanding with the Q&A.
  3. offiste01.jpg (430 bytes) Visit the online Workshop.
    Return here after completing your Workshop session.


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Most recent revision: Thursday, March 20, 2014