how many quarters in a time interval

[jiehuang001]

Sorry to post a mysql question here.

I have two columns start_time, end_time of the datatype "time". For example, for an event, the start_time is 9:00:00, and the end_time is 13:00:00. How to calculate how many quarters (15minutes) for this event? Apparently the following doesn't work.

Select (start_time - end_time)/15 from the_table

[jiehuang001]

I figured it out as following:

select (TIME_TO_SEC(end_time) - TIME_TO_SEC(start_time))/900 as number_of_quarters from the_table;