Question

我想加入3个表

Table employer:
+-------------+-------------+---------+
| employer_id | position_id | shop_id |
+-------------+-------------+---------+
|     1       |      2      |    2    |
|     2       |      2      |    2    |
|     3       |      2      |    2    |
|     4       |      1      |    1    |
|     5       |      1      |    2    |
+-------------+-------------+---------+

Table position:
+-------------+-----------------+
| position_id |  position_name  |
+-------------+-----------------+
|     1       |  Receptionist   |
|     2       |  Secretary      |
+-------------+-----------------+

Table shop:
+---------+-----------+
| shop_id | shop_name |
+---------+-----------+
|    1    | Shop ABC  |
|    2    | Shop DEF  |
+---------+-----------+

这是我的问题：

SELECT S.*, P.*, E.*, COUNT(E.employer_id) AS NumberOfJobs FROM ((shop AS S INNER JOIN employer AS E ON S.shop_id=E.shop_id) INNER JOIN position AS P ON P.position_id=E.position_id) GROUP BY S.shop_id;

我得到的结果：

Shop ABC  
   Receptionist   Job Available : 1  

Shop DEF  
   Secretary      Job Available : 4

但我想要的是：

Shop ABC  
   Receptionist   Job Available : 1  

Shop DEF  
   Receptionist   Job Available : 1    
   Secretary      Job Available : 3

获得我想要的结果的正确查询是什么？感谢有人可以帮我解决这个问题。非常感谢你！

Answer 1

您需要按店铺和位置进行分组，而不仅仅是购物：

SELECT  S._Id , S.Shop_Name
        P.Position_Name ,
        COUNT(E.employer_id) AS NumberOfJobs
FROM    shop AS S
INNER JOIN employer AS E ON S.shop_id = E.shop_id
INNER JOIN position AS P ON P.position_id = E.position_id

GROUP BY S.shop_id, S.Shop_Name, P.Position_Name

如何为这些情况加入3个表

1 个答案: