mysql - 在 mysql 查询中使用最小值、最大值和平均值

Question

我有一个如下所示的表格。

我想在单个查询中获得最低、最高和平均成本产品的 product_id。

CREATE TABLE productlist(product_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
                         cost INT);                             

INSERT INTO productlist(cost)
                 VALUES('2450'),
                       ('2200'),
                       ('2580'),
                       ('2405'),
                       ('3500'),
                       ('1500'),
                       ('1800'),
                       ('1520'),
                       ('1740'),
                       ('1940'),
                       ('2940'),
                       ('1250'),
                       ('1290'),
                       ('1390'),
                       ('2900');

输出:

Min    12
Max    5
Avg    2093

我像下面这样尝试过，但它不起作用。

SELECT product_id, MIN(cost) as mincost
  FROM productlist
 GROUP BY product_id
 ORDER BY mincost ASC
 LIMIT 0,1
 UNION
SELECT product_id, max(cost) as maxcost
  FROM productlist
 GROUP BY product_id
 ORDER BY maxcost DESC
 LIMIT 0,1

我应该怎么做

Answer 1

select 'Min', product_id 
from productlist
where cost = (select min(cost) from productlist)
UNION 
select 'Max', product_id
from productlist
where cost = (select MAX(cost) from productlist)
UNION 
select 'Avg', round(AVG(cost),0) as Avg
from productlist