Hour 15. Combining Multiple Queries into One

Team-Fly    

 
Sams Teach Yourself SQL in 24 Hours, Third Edition
By Ronald R. Plew, Ryan K. Stephens
Table of Contents
Part IV.  Building Sophisticated Database Queries


Hour 15. Combining Multiple Queries into One

During this hour, you learn how to combine SQL queries into one by using the UNION, UNION ALL, INTERSECT, and EXCEPT operators. Once again, you must check your particular implementation for any variations in the use of the UNION, UNION ALL, INTERSECT, and EXCEPT operators.

The highlights of this hour include

  • 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

graphics/note_icon.gif

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.



Team-Fly    
Top
 


Sams Teach Yourself SQL in 24 Hours
Sams Teach Yourself SQL in 24 Hours (5th Edition) (Sams Teach Yourself -- Hours)
ISBN: 0672335417
EAN: 2147483647
Year: 2002
Pages: 275

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net