我已简化了我的问题并创建了此示例以更好地说明。sql。获得最大值(平均值(列))
我的表:
CREATE TABLE `table_company` (
`source_id` INT(10) UNSIGNED NOT NULL,
`company_id` INT(10) UNSIGNED NOT NULL,
`clicks` INT(10) UNSIGNED NOT NULL,
PRIMARY KEY (`source_id`,`company_id`)
) ENGINE=INNODB DEFAULT CHARSET=utf8;
我的数据:
INSERT INTO table_company VALUES
(1,100,8),(2,100,7),(3,200,9),(4,300,3),(5,100,4),(6,400,5),(7,100,10),(8,500,4),(9,500,9),(10,400,9);
SELECT source_id,company_id,AVG(clicks) AS avg_click FROM table_company
GROUP BY source_id,company_id
ORDER BY avg_click DESC;
给我:
source_id company_id avg_click
--------- ---------- -----------
7 100 10.0000
3 200 9.0000
9 500 9.0000
10 400 9.0000
1 100 8.0000
2 100 7.0000
6 400 5.0000
5 100 4.0000
8 500 4.0000
4 300 3.0000
我想编写一个查询给我:
source_id company_id avg_click
--------- ---------- -----------
7 100 10.0000
3 200 9.0000
9 500 9.0000
10 400 9.0000
4 300 3.0000
即。只有保持这种有MAX(avg_click)的COMPANY_ID
感谢。我有类似的东西,但没有正确执行我的外部GROUP BY。 – Yada