在sql中汇总列

我有一个要求，我想要以下结果集：

Type       Receipts Issues Balance
==================================
Purchase    10       0     10
Purchase    5        0     15
Sales       0        2     13  
Purchase    10       0     23
Sales       0        5     18

其中，最后一列应为汇总余额=（收据和问题）+余额

我的问题是：

SELECT type, 
       Isnull(receipts, 0)                         AS Receipts, 
       Isnull(issues, 0)                           AS Issues, 
       ( Isnull(receipts, 0) - Isnull(issues, 0) ) AS Balance 
FROM   (SELECT 'Purchasse' AS Type, 
               PBD.qty     AS Receipts, 
               NULL        AS Issues 
        FROM   tbl_purchasebillmain PB 
               JOIN tbl_purchasebilldetail PBD 
                 ON PBD.purchasebill_id = PB.record_id 
               JOIN tbl_product_master PM 
                 ON PM.record_id = PBD.product_id 
        UNION 
        SELECT 'Purchasse Return' AS Type, 
               NULL               AS Receipts, 
               PRD.qty            AS Issues 
        FROM   dbo.tbl_purchasereturnmain PR 
               JOIN dbo.tbl_purchasereturndetail PRD 
                 ON PRD.purchasereturnbill_id = PR.record_id 
               JOIN tbl_purchasebilldetail PBD 
                 ON PBD.record_id = PRD.purchasebilldetail_id 
               JOIN tbl_product_master PM 
                 ON PM.record_id = PBD.product_id) AS s 

---

我不确定你所说的（收据问题）+余额是什么意思，但我假设你想要这个：

SELECT type, 
       sum(Isnull(receipts, 0))                         AS Receipts, 
       sum(Isnull(issues, 0))                           AS Issues, 
       sum(( Isnull(receipts, 0) - Isnull(issues, 0) )) AS Balance 
FROM   (SELECT 'Purchasse' AS Type, 
               PBD.qty     AS Receipts, 
               NULL        AS Issues 
        FROM   tbl_purchasebillmain PB 
               JOIN tbl_purchasebilldetail PBD 
                 ON PBD.purchasebill_id = PB.record_id 
               JOIN tbl_product_master PM 
                 ON PM.record_id = PBD.product_id 
        UNION 
        SELECT 'Purchasse Return' AS Type, 
               NULL               AS Receipts, 
               PRD.qty            AS Issues 
        FROM   dbo.tbl_purchasereturnmain PR 
               JOIN dbo.tbl_purchasereturndetail PRD 
                 ON PRD.purchasereturnbill_id = PR.record_id 
               JOIN tbl_purchasebilldetail PBD 
                 ON PBD.record_id = PRD.purchasebilldetail_id 
               JOIN tbl_product_master PM 
                 ON PM.record_id = PBD.product_id) AS s 
group by type

---

您是得到了错误还是根本没有得到想要的结果？在这个表上有一个自动递增的id会很有趣，这样，您就可以从子查询中获取当前id-1的余额。不知道是不是你想要别的，别担心：）@Jakob，我没有得到我期望的结果