Sorting a Result Set

3.16.1 Problem

Your query results aren't sorted the way you want.

3.16.2 Solution

MySQL can't read your mind. Add an ORDER BY clause to tell it exactly how you want things sorted.

3.16.3 Discussion

When you select rows, the MySQL server is free to return them in any order, unless you instruct it otherwise by saying how to sort the result. There are lots of ways to use sorting techniques. Chapter 6 explores this topic further. Briefly, you sort a result set by adding an ORDER BY clause that names the column or columns you want to sort by:

mysql> SELECT * FROM mail WHERE size > 100000 ORDER BY size;
+---------------------+---------+---------+---------+---------+---------+
| t | srcuser | srchost | dstuser | dsthost | size |
+---------------------+---------+---------+---------+---------+---------+
| 2001-05-12 12:48:13 | tricia | mars | gene | venus | 194925 |
| 2001-05-15 10:25:52 | gene | mars | tricia | saturn | 998532 |
| 2001-05-14 17:03:01 | tricia | saturn | phil | venus | 2394482 |
+---------------------+---------+---------+---------+---------+---------+
mysql> SELECT * FROM mail WHERE dstuser = 'tricia'
 -> ORDER BY srchost, srcuser;
+---------------------+---------+---------+---------+---------+--------+
| t | srcuser | srchost | dstuser | dsthost | size |
+---------------------+---------+---------+---------+---------+--------+
| 2001-05-15 10:25:52 | gene | mars | tricia | saturn | 998532 |
| 2001-05-14 11:52:17 | phil | mars | tricia | saturn | 5781 |
| 2001-05-17 12:49:23 | phil | mars | tricia | saturn | 873 |
| 2001-05-11 10:15:08 | barb | saturn | tricia | mars | 58274 |
| 2001-05-13 13:59:18 | barb | saturn | tricia | venus | 271 |
+---------------------+---------+---------+---------+---------+--------+

To sort a column in reverse (descending) order, add the keyword DESC after its name in the ORDER BY clause:

mysql> SELECT * FROM mail WHERE size > 50000 ORDER BY size DESC;
+---------------------+---------+---------+---------+---------+---------+
| t | srcuser | srchost | dstuser | dsthost | size |
+---------------------+---------+---------+---------+---------+---------+
| 2001-05-14 17:03:01 | tricia | saturn | phil | venus | 2394482 |
| 2001-05-15 10:25:52 | gene | mars | tricia | saturn | 998532 |
| 2001-05-12 12:48:13 | tricia | mars | gene | venus | 194925 |
| 2001-05-14 14:42:21 | barb | venus | barb | venus | 98151 |
| 2001-05-11 10:15:08 | barb | saturn | tricia | mars | 58274 |
+---------------------+---------+---------+---------+---------+---------+

Using the mysql Client Program

Writing MySQL-Based Programs

Record Selection Techniques

Working with Strings

Working with Dates and Times

Sorting Query Results

Generating Summaries

Modifying Tables with ALTER TABLE

Obtaining and Using Metadata

Importing and Exporting Data

Generating and Using Sequences

Using Multiple Tables

Statistical Techniques

Handling Duplicates

Performing Transactions

Introduction to MySQL on the Web

Incorporating Query Resultsinto Web Pages

Processing Web Input with MySQL

Using MySQL-Based Web Session Management

Appendix A. Obtaining MySQL Software

Appendix B. JSP and Tomcat Primer

Appendix C. References



MySQL Cookbook
MySQL Cookbook
ISBN: 059652708X
EAN: 2147483647
Year: 2005
Pages: 412
Authors: Paul DuBois

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