TABLE 1: Current and Previous Contract Details
Custid cdate amount prev_amount
1 2001-01-18 00:00:00 10000 NULL
1 2001-04-13 00:00:00 90000 10000
1 2001-08-28 00:00:00 75000 90000
1 2001-10-08 00:00:00 80000 75000
2 2001-01-09 00:00:00 65000 NULL
2 2001-05-07 00:00:00 50000 65000
2 2001-08-03 00:00:00 35000 50000
2 2001-09-19 00:00:00 90000 35000
2 2001-10-12 00:00:00 60000 90000
3 2001-03-04 00:00:00 55000 NULL
3 2001-06-21 00:00:00 40000 55000
3 2001-09-28 00:00:00 75000 40000
4 2001-02-12 00:00:00 95000 NULL