如何加入3代表對這些情況

Question

我想加入3個表

 
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 | 
+---------+-----------+ 

這裏是我的查詢：

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; 

結果我得到：

 
Shop ABC 
    Receptionist Job Available : 1 

Shop DEF 
    Secretary  Job Available : 4 

但什麼我想要的是：

 
Shop ABC 
    Receptionist Job Available : 1 

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

什麼是正確的查詢來獲得我想要的結果？感謝有人能幫助我解決這個問題。非常感謝你！

Answer 1

你需要按商店和位置，而不僅僅是開店：

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