我有这样的作业表
EMPLID | RCD | COMPANY | EFFDT | SALARY
---------------------------------------------------
100 | 0 | xyz | 1/1/2000 | 1000
100 | 0 | xyz | 1/15/2000 | 1100
100 | 0 | xyz | 1/31/2000 | 1200
100 | 0 | ggg | 2/15/2000 | 1500
100 | 1 | abc | 3/1/2000 | 2000
100 | 1 | abc | 4/1/2000 | 2100
我需要一个计数器,当RCD或公司组合发生变化时,该计数器应该增加,并且应该由effdt订购.
EMPLID | RCD | COMPANY | EFFDT | SALARY | COUNTER
-------|-----|---------|---------------|-------------|----------
100 | …