Question

我有两张桌子

Master  
Detail

在Master＆amp;细节表，我有一个Amount字段

我需要获得Amount的详细信息并从Master中减去Amount并显示在“Current_Amount”中

“Current_Amount”应该等于“Master.Amount” - “Detail.Amount”的总和

Answer 1

如果两张桌子上没有大量细节，这将为您提供总数：

SELECT (Max(M.Amount) - SUM(D.Amount)) as CurrentAmount
FROM Master M
INNER JOIN Detail D
    ON M.ID = D.ID

然后，如果你想要包括主Id：

SELECT M.ID, (Max(M.Amount) - SUM(D.Amount)) as CurrentAmount
FROM Master M
INNER JOIN Detail D
    ON M.ID = D.ID
GROUP BY M.ID

Answer 2

尝试：

select m.ID, max(m.Amount) - sum(d.Ammount) Current_Amount
from Master m
left join Detail D on m.ID = d.Master_ID
group by m.ID

- 假设Master主键ID存储在Detail作为Master_ID。

Answer 3

由于您没有指定...

，因此会对连接条件进行假设

SELECT     Master.ID,
           (MAX(Master.Amount) - ISNULL(SUM(Detail.Amount), 0)) AS Current_Amount
FROM       Master
LEFT JOIN  Detail ON Detail.MasterID = Master.ID
GROUP BY   Master.ID

注意： MAX(Master.Amount)只是无需在group by子句中指定Master.Amount。

在主细节SQL语句中汇总详细记录

3 个答案: