sql做连续减法怎么办？
(isnull((select sum(cq_dinner) from cjf_card_dzcq where cq_cardno=a.c_incode and cq_type='04' and cq_ctime<=:etime),0) -isnull((select sum(cq_dinner) from cjf_card_dzcq where cq_cardno=a.c_incode and cq_type='03' and cq_ctime<=:etime),0) ) as totaldinner//通过(isnull((select sum(cq_dinner) from cjf_card_dzcq where cq_cardno=a.c_incode and cq_type='04' and cq_ctime<=:etime),0) -isnull((select sum(cq_dinner) from cjf_card_dzcq where cq_cardno=a.c_incode and cq_type='05' and cq_ctime<=:etime),0) -isnull((select sum(cq_dinner) from cjf_card_dzcq where cq_cardno=a.c_incode and cq_type='03' and cq_ctime<=:etime),0) ) as totaldinner-//通不过
