How do I calculate minutes worked by 15 intervals?

[Yammi]

Ok, I know that there is a very smart programmer out there that can resovle my issue.

I am trying to calculate time worked by 15 minute intervals.

Example:
=============== ==
Emp 1 started work at 13:00:00 and worked 183 minutes
Emp 2 started work at 17:15:00 and worked 150 minutes
Emp 3 started work at 08:30:00 and worked 17 minutes

Note: minutes / 15 = total number of of intervals
183 minutes / 15 = 12.2 (intervals)
12 x 15 =180
.2 x 15 = 3 minutes overage - this overage would be placed into the next time slot (see below).

I need to show the following results:

time employee #of_min_worked
----------------------------------------------
08:30:00 3 15
08:45:00 3 2
09:00:00
08:30:00
08:45:00
09:00:00
09:15:00
09:30:00
09:45:00
10:00:00
10:15:00
10:30:00
10:45:00
11:00:00
11:15:00
11:30:00
11:45:00
12:00:00
12:15:00
12:30:00
12:45:00
13:00:00 1 15
13:15:00 1 15
13:30:00 1 15
13:45:00 1 15
14:00:00 1 15
14:15:00 1 15
14:30:00 1 15
14:45:00 1 15
15:00:00 1 15
15:15:00 1 15
15:30:00 1 15
15:45:00 1 15
16:00:00 1 3
16:15:00
16:30:00
16:45:00
17:00:00
17:15:00 2 15
17:30:00 2 15
17:45:00 2 15
18:00:00 2 15
18:15:00 2 15
18:30:00 2 15
18:45:00 2 15
19:00:00 2 15
19:15:00 2 15
19:30:00 2 15
19:45:00
20:00:00
20:15:00
20:30:00
20:45:00
21:00:00
21:15:00
21:30:00
21:45:00
22:00:00
22:15:00
22:30:00
22:45:00
23:00:00
23:15:00
23:30:00
23:45:00

[caveatashish]

do you want the same to be achieved using sql procedure or some other frontend language