select sum(SELECT isnull(sum(CONTRACT_PAYMENT_APPLY_BILL.INVEST_VALUE),0.00) FROM CONTRACT_PAYMENT_APPLY_BILL where CONTRACT_ID=277 GROUP BY month(apply_date)) as TZWCLJ from CONTRACT_PAYMENT_APPLY_BILL where month(apply_date)<4
楼主,你这sql是有问题的:
SELECT isnull(sum(CONTRACT_PAYMENT_APPLY_BILL.INVEST_VALUE),0.00) FROM CONTRACT_PAYMENT_APPLY_BILL where CONTRACT_ID=277 GROUP BY month(apply_date)
这个可是一个记录集,而不是一个字段列(即使他返回的仅仅一行数据,他还是一个记录集)