October 2002
Intermediate to advanced
1024 pages
27h 26m
English
This chapter covers sorting, an
operation that is extremely important for controlling how MySQL
displays results from SELECT statements. Sorting
is performed by adding an ORDER
BY clause to a query. Without such a clause, MySQL
is free to return rows in any order, so sorting helps bring order to
disorder and make query results easier to examine and understand.
(Sorting also is performed implicitly when you use a
GROUP BY clause, as discussed
in Recipe 7.14.)
One of the tables used for quite a few examples in this chapter is
driver_log, a table that contains columns for
recording daily mileage logs for a set of truck drivers:
mysql> SELECT * FROM driver_log;
+--------+-------+------------+-------+
| rec_id | name | trav_date | miles |
+--------+-------+------------+-------+
| 1 | Ben | 2001-11-30 | 152 |
| 2 | Suzi | 2001-11-29 | 391 |
| 3 | Henry | 2001-11-29 | 300 |
| 4 | Henry | 2001-11-27 | 96 |
| 5 | Ben | 2001-11-29 | 131 |
| 6 | Henry | 2001-11-26 | 115 |
| 7 | Suzi | 2001-12-02 | 502 |
| 8 | Henry | 2001-12-01 | 197 |
| 9 | Ben | 2001-12-02 | 79 |
| 10 | Henry | 2001-11-30 | 203 |
+--------+-------+------------+-------+Many other examples use the mail table (first seen
in earlier chapters):
mysql> SELECT * FROM mail; +---------------------+---------+---------+---------+---------+---------+ | t | srcuser | srchost | dstuser | dsthost | size | +---------------------+---------+---------+---------+---------+---------+ | 2001-05-11 ...