How to round a time to the nearest 15 minute segment

Question

How can I round times in MySQL to the nearest 15 minutes (e.g. 0,15,30,45)?

Answer 1

SELECT SEC_TO_TIME(FLOOR((TIME_TO_SEC(CURTIME())+450)/900)*900)

In this example I have used CURTIME() for the input time, but you can use any time field.

900 seconds=15 minutes (the period to round to), 450 seconds is half that (to provide the rounding element). I've tested with 1800/900 to get nearest half hour, should work with others (600/300 for 10 minutes etc).