Recipe 7.8. Sorting by Time of Day
ProblemYou want to sort rows in time-of-day order. SolutionPull out the hour, minute, and second from the column that contains the time, and use them for sorting. DiscussionTime-of-day sorting can be done different ways, depending on your column type. If the values are stored in a TIME column named timecol, just sort them directly using ORDER BY timecol. To put DATETIME or TIMESTAMP values in time-of-day order, extract the time parts and sort them. For example, the mail table contains DATETIME values, which can be sorted by time of day like this: mysql> SELECT * FROM mail ORDER BY HOUR(t), MINUTE(t), SECOND(t); +---------------------+---------+---------+---------+---------+---------+ | t | srcuser | srchost | dstuser | dsthost | size | +---------------------+---------+---------+---------+---------+---------+ | 2006-05-15 07:17:48 | gene | mars | gene | saturn | 3824 | | 2006-05-15 08:50:57 | phil | venus | phil | venus | 978 | | 2006-05-16 09:00:28 | gene | venus | barb | mars | 613 | | 2006-05-14 09:31:37 | gene | venus | barb | mars | 2291 | | 2006-05-11 10:15:08 | barb | saturn | tricia | mars | 58274 | | 2006-05-15 10:25:52 | gene | mars | tricia | saturn | 998532 | | 2006-05-14 11:52:17 | phil | mars | tricia | saturn | 5781 | | 2006-05-12 12:48:13 | tricia | mars | gene | venus | 194925 | ... You can also use TIME_TO_SEC( ), which strips off the date part and returns the time part as the corresponding number of seconds: mysql> SELECT * FROM mail ORDER BY TIME_TO_SEC(t); +---------------------+---------+---------+---------+---------+---------+ | t | srcuser | srchost | dstuser | dsthost | size | +---------------------+---------+---------+---------+---------+---------+ | 2006-05-15 07:17:48 | gene | mars | gene | saturn | 3824 | | 2006-05-15 08:50:57 | phil | venus | phil | venus | 978 | | 2006-05-16 09:00:28 | gene | venus | barb | mars | 613 | | 2006-05-14 09:31:37 | gene | venus | barb | mars | 2291 | | 2006-05-11 10:15:08 | barb | saturn | tricia | mars | 58274 | | 2006-05-15 10:25:52 | gene | mars | tricia | saturn | 998532 | | 2006-05-14 11:52:17 | phil | mars | tricia | saturn | 5781 | | 2006-05-12 12:48:13 | tricia | mars | gene | venus | 194925 | ... |
