SQL連接或子查詢合併總比賽

Question

我有一個命名爲表：

• 用戶
• userAccount
• userRight

與1對多的關係。

我在找的是一個查詢，它會給我賬戶總數&的權利。

例如：

user: a 
account: 1, 2, 3 
right: a, b, c 

user b 
account: 1, 2 
right: 

user c: 
account: 1 
right: e, f, g, h 

應該返回結果的數量以降序

a 6 
c 5 
b 2 

我是有密切的使用連接和分組排序的，但我最終得到一個：9作爲其獲得3 x 3條記錄。

Answer 1

嘗試以下一個

SELECT user_name,(SELECT COUNT(*) FROM userRight WHERE user_id=u.user_id) + 
(SELECT COUNT(*) FROM userAccount WHERE user_id=u.user_id) AS total 
FROM user u ORDER BY total DESC 

，如果你想用戶總數到WHERE子句然後

SELECT user_name,(SELECT COUNT(*) FROM userRight WHERE user_id=u.user_id) + 
(SELECT COUNT(*) FROM userAccount WHERE user_id=u.user_id) AS total 
FROM user u WHERE ((SELECT COUNT(*) FROM userRight WHERE user_id=u.user_id) + 
(SELECT COUNT(*) FROM userAccount WHERE user_id=u.user_id))>10 ORDER BY total DESC