應用DISTINT不工作

Question

我的查詢基於炒鍋表（三個部分）的結果應該是13000，但我得到39000

# Order table 

------------------------------------------- 
| Id | order    | Name | Fee | 
------------------------------------------- 
| 1 | SELECT STATEMENT | ab | 13000 | 
------------------------------------------- 

# Work table 
----------------------------- 
| Id | user id | order id | 
----------------------------- 
| 1 | 123 | 1  | 
| 2 | 123 | 1  | 
| 3 | 123 | 1  | 
----------------------------- 


# Query 
SELECT o.order_id, SUM(o.fee) AS total_words 
FROM users AS u 
LEFT JOIN works AS wr ON wr.user_id = u.id 
LEFT JOIN orders AS o ON o.order_id = wr.order_id 
    WHERE u.id = 123 

# Output =>  
Array 
(
    [order_id] => 1 
    [fee] => 39000 
) 

我試圖總結DISTINCT費然後分組，但是我得到相同的結果。

Answer 1

SQL Fiddle Demo

SELECT `user_id`, SUM(orders.`Fee`) 
FROM (SELECT DISTINCT `user_id`, `order_id` 
     FROM works 
    ) as user_work 
JOIN orders 
    ON user_work.`order_id` = orders.`Id` 
WHERE user_work.user_id = 123 

輸出

| user_id | SUM(orders.`Fee`) | 
|---------|-------------------| 
|  123 |    13000 |