MYSQL Date Time Round To Nearest Hour

Question

I have a date time field in a MySQL database and wish to output the result to the nearest hour.

e.g. 2012-04-01 00:00:01 should read 2012-04-01 00

Answer 1

I think this is the best way, since it also will use the least amount of resources-

date_add(date(date_completed), interval hour(date_completed) hour) as date_hr