rounding to 15 seconds

Hi,

I have a process that retrieves a stock quote, roughly, every 15 seconds. I'd like to round the date to every 15 seconds, so that the dates end on 0, 15, 30, 45 seconds.

I can't think of a way to do this in sql. I was hoping someone here could :)

below is a sample of the data

Thanks
Jake

SQL> select quotedate from quote where quotedate > '2003/09/22';

QUOTEDATE

2003/09/22 08:30:04
2003/09/22 08:30:20
2003/09/22 08:30:35
2003/09/22 08:30:50
2003/09/22 08:31:05
2003/09/22 08:31:21
2003/09/22 08:31:36
2003/09/22 08:31:51
2003/09/22 08:32:06
2003/09/22 08:32:21
2003/09/22 08:32:36