vb，如何把一个表的多次金额汇总到另一个表对应的记录里？

我有一个支付金额的表和一个总表，现在需要把一个合同多次支付的的金额加以来放到总表对应的合同名称的总金额里。请问如何实现？请高手详细说明。sql = "select cno,contractname,clientname,signing_time,amount,memo,payment,unpaid , (select sum(pay_amount) from jjpay where contractname = jjhetong.contractname )from jjhetong "

(select contractname,sum(pay_amount) as SUM1 from jjpay group by contractname)

jjhetong是总表,jjpay是支付表

update jjhetong set 总额字段=A.sum1 from (select contractname,sum(pay_amount) as SUM1 from jjpay group by contractname) as A where A.contractname=jjhetong.contractname;

一次统计支付表中所有与总表对应的记录,并更新到总表对应的"总额字段"(语句中"总额字段" 根据总表的实际更改).

sql = "select cno,contractname,clientname,signing_time,amount,memo,payment,unpaid , (select sum(pay_amount) as SUM1 from jjpay where contractname = jjhetong.contractname )from jjhetong "

如果此记录集是：RSSUM 总表的记录集为：RSZ RSZ（"字段名"）=RSSUM（"SUM1"） 即可了，当然，具体代码就不用给出了吧