Question

请帮我执行此查询。我已经做了所有事情，但我认为我的查询不起作用。请帮忙。

表

ITEM
     id     Name      
     1      Computer 1
     2      Computer 2


STATUS
    id    Stat_Name
    1     Stock In
    2     Stock Out

INVENTORY
    id    Item_id    Status_id  Quantity
    1     1          1          100
    2     1          2          200
    3     1          1          30
   4     2          1          35
   5     2          2          36

我想要这个输出输出：

Item        overall_stock_in    overall_stock_out
    Computer1   130                 200
    Computer2   35                  36

谢谢大家

Answer 1

试试这个：

SELECT 
  B.Id,
  B.Name, 
  SUM(CASE WHEN A.Status_id=1 THEN A.Quantity ELSE 0 END) AS overall_stock_in,
  SUM(CASE WHEN A.Status_id=2 THEN A.Quantity ELSE 0 END) AS overall_stock_out
FROM INVENTORY A JOIN ITEM B ON A.Item_id=B.id
GROUP BY B.Id, B.Name
ORDER BY B.Name;

请参阅DEMO on SQL Fiddle。

Answer 2

也使用状态表（更新了@ cdaiga的查询）：

SELECT 
C.Name, 
SUM(CASE WHEN B.Status_Name='Stock In' THEN A.Quantity ELSE 0 END) AS 
overall_stock_in,
SUM(CASE WHEN B.Status_Name='Stock Out' THEN A.Quantity ELSE 0 END) AS 
overall_stock_out
FROM INVENTORY A JOIN ITEM C ON A.Item_id=C.id
JOIN "status" B ON A.Status_id=B.id
GROUP BY C.Name
ORDER BY C.Name;

我的项目的复杂Sql查询

2 个答案: