Time difference between records

I need to find a method (sql, plsql) to find the time difference between records

Example,

Ticket#      Operation    Time
A1             Modify         1000
A1             Modify         1100
A1             Modify         1300
A2             Modify         0900
A2             Modify         0930

Should produce something like:

A1 1 hour
A1 2 hours
A2 30 minutes

Has anyone done this before? Received on Tue Sep 14 2004 - 09:49:57 CDT