SELECT a.ProductID, SUM(b.Amount) as 出入库物资数量, SUM(b.Money) as 出入库物资金额
FROM tblProduct AS a LEFT JOIN tblIn AS b ON a.ProductID=b.ProductID
GROUP BY a.ProductID
union all
SELECT a.ProductID, SUM(c.Amount)*-1 , SUM(c.Money)
FROM tblProduct AS a LEFT JOIN tblOut AS c ON a.ProductID=c.ProductID
GROUP BY a.ProductID
FROM tblProduct AS a LEFT JOIN tblIn AS b ON a.ProductID=b.ProductID
GROUP BY a.ProductID
union all
SELECT a.ProductID, SUM(c.Amount)*-1 , SUM(c.Money)
FROM tblProduct AS a LEFT JOIN tblOut AS c ON a.ProductID=c.ProductID
GROUP BY a.ProductID
(SELECT a.ProductID, SUM(b.Amount) as 入库物资数量, SUM(b.Money) as 入库物资金额
FROM tblProduct AS a LEFT JOIN tblIn AS b ON a.ProductID=b.ProductID
GROUP BY a.ProductID)t1 full join
(SELECT a.ProductID, SUM(c.Amount)as 出库物资数量 , SUM(c.Money)as 出库物资金额
FROM tblProduct AS a LEFT JOIN tblOut AS c ON a.ProductID=c.ProductID
GROUP BY a.ProductID)t2
on t1.productid=t2.productid
我以前也是像天涯沦落人一样写的,但是语法有错误,能告诉我错在哪里吗?