我的下表如下：
ID ACTION_DATE AMOUNT ACTION_TYPE
--------------------------------------------------------
1 01-JAN-18 12.37.44.232000000 AM 24 Dr
1 01-JAN-18 12.38.16.928000000 AM 30 Dr
1 01-JAN-18 01.20.18.435000000 AM 200 Cr
1 01-JAN-18 01.35.43.462000000 AM 15 Dr
1 01-JAN-18 01.43.42.925000000 AM 30 Dr
1 01-JAN-18 01.49.23.746000000 AM 23 Dr
1 01-JAN-18 01.49.52.190000000 AM 26 Dr
2 01-JAN-18 12.37.44.232000000 AM 40 Dr
2 01-JAN-18 12.38.16.928000000 AM 50 Dr
2 01-JAN-18 01.20.18.435000000 AM 100 CR
2 01-JAN-18 01.35.43.462000000 AM 15 Dr
2 01-JAN-18 01.43.42.925000000 AM 20 Dr
2 01-JAN-18 01.49.23.746000000 AM 25 Dr
2 01-JAN-18 01.49.52.190000000 AM 30 Dr
，目标表将为
ID ACTION_DATE AMOUNT ACTION_TYPE Acc_amount
---------------------------------------------------------------
1 01-JAN-18 12.37.44.232000000 AM 24 Dr 24
1 01-JAN-18 12.38.16.928000000 AM 30 Dr 54
1 01-JAN-18 01.20.18.435000000 AM 200 Cr 0
1 01-JAN-18 01.35.43.462000000 AM 15 Dr 15
1 01-JAN-18 01.43.42.925000000 AM 30 Dr 45
1 01-JAN-18 01.49.23.746000000 AM 23 Dr 68
1 01-JAN-18 01.49.52.190000000 AM 26 Dr 84
2 01-JAN-18 12.37.44.232000000 AM 40 Dr 40
2 01-JAN-18 12.38.16.928000000 AM 50 Dr 90
2 01-JAN-18 01.20.18.435000000 AM 100 CR 0
2 01-JAN-18 01.35.43.462000000 AM 15 Dr 15
2 01-JAN-18 01.43.42.925000000 AM 20 Dr 35
2 01-JAN-18 01.49.23.746000000 AM 25 Dr 60
2 01-JAN-18 01.49.52.190000000 AM 30 Dr 90
我尝试使用over和partition by作为
select id, action_date,action_type, amount,
sum(amount) over (partition by id order by action_date) as acc_amount
from cashanalysis order by id,action_date;
一旦action_type ='Cr'，如何将acc_amount释放为零
感谢您的帮助