Sams Teach Yourself SQL in 24 Hours, Fifth Edition

Hour 10. Sorting and Grouping Data

What You’ll Learn in This Hour:

• Why you would want to group data

• The GROUP BY clause

• Group value functions

• The how and why of group functions

• Grouping by columns

• GROUP BY versus ORDER BY

• The HAVING clause

You have learned how to query the database and return data in an organized fashion. You have also learned how to sort data from a query. During this hour, you learn how to break returned data from a query into groups for improved readability.

Why Group Data?

Grouping data is the process of combining columns with duplicate values in a logical order. For example, a database might contain information about employees; many employees live in different cities, but some employees live in the same ...