Question

我想制作一个简单的视图，以便查看来自不同仓库的库存总和是否> 0且＆lt;该产品的最低库存量。

以下是代码：

SELECT a.code, a.description, a.stk_min , b.Stk_Qty
FROM a 
INNER JOIN b ON a.code = b.productcode
WHERE a.stk_min > 0 and 

     (SELECT SUM(b.Stk_Qty )
     FROM b
     INNER JOIN a ON a.code = b.productcode
     Group By a.code) <= a.stk_min

当然我收到了错误

子查询返回的值超过1。当子查询跟随=，!=，<，<=，>，>=或子查询被用作子查询时，不允许这样做表达。

我有什么办法可以改变这个吗？

Answer 1

您正在寻找相关子查询，而不是group by。此查询应该可以解决问题：

SELECT a.code, a.description, a.stk_min , b.Stk_Qty
FROM a JOIN
     b
     ON a.code = b.productcode
WHERE a.stk_min > 0 and 
      (SELECT SUM(b.Stk_Qty )
       FROM b2 
       WHERE a.code = b2.productcode
      ) <= a.stk_min;

我怀疑你想要这个：

SELECT a.code, a.description, a.stk_min, SUM(b.Stk_Qty)
FROM a LEFT JOIN
     b
     ON a.code = b.productcode
WHERE a.stk_min > 0
GROUP BY a.code, a.description, a.stk_min
HAVING COALESCE(SUM(b.Stk_Qty), 0) < a.stk_min;

Answer 2

怎么样？

SELECT a.code, a.description, a.stk_min, SUM(b.Stk_Qty) SumQty
FROM a join b on b.productcode = a.code 
group by a.code, a.description, a.stk_min
Where a.stk_min > 0
Having   SUM(b.Stk_Qty) <= a.stk_min

由于where和group by，子查询返回的值超过1

2 个答案: