sql 面试题5

1,现有表bill和表payment结构如下，两表通过pay_id关联：
bill表――bill_id是帐单标识，charge为帐单金额，pay_id为付款编号，PK：bill_id
bill_id INTEGER
charge INTEGER
pay_id INTEGER

payment表――pay_id为付款编号，charge为付款金额，PK：pay_id
pay_id INTEGER
charge INTEGER

要求更新payment使charge=bill表中同一pay_id的charge之和。

select pay_id,charge=sum(charge) into #temp from bill group by pay_id
update payment set payment.charge=#temp.charge from payment,#temp where payment.pay_id=#temp.pay_id