Question

我有两张桌子，一张用于销售，另一张用于库存。我想从销售表中选择位置ID，商品ID，尺寸ID和销售数量，而我只想从库存表中选择库存数量来获取销售表中相同的位置ID和尺寸ID，如下所示：

销售表：

------------------------------------
| loc_id | item_id | size_id | qty |
------------------------------------
|   5    |  11321  |    1    |  3  |
|   5    |  11321  |    2    |  7  |
|   5    |  11321  |    3    |  9  |

股票表：

------------------------------------------------------
| loc_id | item_id | size_id | sales_qty | stock_qty |
------------------------------------------------------
|   5    |  11321  |    1    |     5     |     3     |
|   5    |  11321  |    2    |     9     |     7     |
|   5    |  11321  |    3    |     4     |     9     |

所以select之后的结果应该是这样的：

SELECT SUM(T1.qty) AS `salesQty`, SUM(T2.qty) AS `stockQty`, T1.size_id,
T1.loc_id
FROM sales T1
INNER JOIN stock T2 ON T2.item_id = T1.item_id AND T2.size_id = T1.size_id 
WHERE T1.item_id = '11321'
AND T1.size_id IN (1,2,3)
AND T1.loc_id IN (5)
GROUP BY T1.size_id, T1.loc_id

这是我尝试做的事情：

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但库存数量总是错误的！

Answer 1

select
   q1.loc_id
  ,q1.item_id
  ,q1.size_id
  ,sum(case when q1.Type='Sales' then q1.Qty else 0 end) as sales_qty
  ,sum(case when q1.Type='Stock' then q1.Qty else 0 end) as stock_qty
from (

select
   T1.loc_id
  ,T1.item_id
  ,T1.size_id
  ,'Sales' as Type
  ,SUM(T1.qty) AS Qty  
from sales T1
group by
   T1.loc_id
  ,T1.item_id
  ,T1.size_id

union all

select
   T2.loc_id
  ,T2.item_id
  ,T2.size_id
  ,'Stock' as Type
  ,SUM(T2.qty) AS Qty  
from stock T2
group by
   T2.loc_id
  ,T2.item_id
  ,T2.size_id) q1

group by
   q1.loc_id
  ,q1.item_id
  ,q1.size_id

在一个结果表中组合多个select语句

1 个答案: