Mysql查詢與分組並具有子句

Question

我正在構建查詢以獲得同一產品的最高價格。 我有表作爲

----------------------------------------- 
| prod_id | price | user_id | 
----------------------------------------- 
|  4  | 25  |  1  | 
|  4  | 38  |  2  | 
|  4  | 41  |  3  | 
|  7  | 100  |  1  | 
|  7  | 95  |  2  | 
----------------------------------------- 

我試圖讓下面的輸出：

----------------------------------------- 
|  4  | 41  |  3  | 
----------------------------------------- 
|  7  | 100  |  1  | 
----------------------------------------- 

我構建以下查詢這是不正確的。

select * from user_bid group by prod_id having max(price); 

有人可以指導我查詢所需的結果。

Answer 1

SELECT * 
FROM user_bid 
WHERE (prodid, price) IN 
(
    SELECT prodid, MAX(price) 
    FROM user_bid 
    GROUP BY prod_id 
) 

Answer 2

下面是使用一個選項加入：

SELECT p1.* 
FROM prod_id 
INNER JOIN 
(
    SELECT prod_id, MAX(price) AS price -- this inner subquery finds the maximum 
    FROM user_bid       -- price for each product group 
    GROUP BY prod_id 
) p2 
    ON p1.prod_id = p2.prod_id AND   -- and this join condition retains 
     p1.price = p2.price    -- only records which have this maximum 
              -- price for each product group 

在此可以使用子查詢的選項：

SELECT p1.* 
FROM prod_id p1 
WHERE price = (SELECT MAX(p2.price) FROM prod_id p2 WHERE p1.prod_id = p2.prod_id) 

Answer 3

對於SQL Server

;WITH cte AS 

(
SELECT prod_id,price,user_id, 
     ROW_NUMBER() OVER(PARTITION BY prod_id ORDER BY price desc) as rank 
FROM table Name 
) 

SELECT prod_id,price,user_id 
FROM cte 
WHERE rank=1 

Answer 4

使用以下查詢：

SELECT * FROM (SELECT * FROM user_bid ORDER BY price DESC) AS Temp 
GROUP BY prod_id 

輸出：