mysql group by和max [重复]

Posted 2023-02-24

【中文标题】mysql group by和max [重复]

【英文标题】：mysql group by and max [duplicate]

【发布时间】：2018-06-29 04:31:24

【问题描述】：

我在mysql中有这个表：

+----+------+------------+-------+
| id | code |    date    | value |
+----+------+------------+-------+
| 1  |   3  | 2016-01-01 |   3   |
| 2  |   3  | 2016-01-02 |   4   |
| 3  |   3  | 2016-03-01 |   6   |
| 4  |   3  | 2016-06-06 |   5   |
| 5  |   8  | 2016-01-01 |   1   |
| 6  |   8  | 2016-09-09 |   3   |
+----+------+------------+-------+

我想返回一个这样的表：

+------+------------+-------+
| code |    date    | value |
+------+------------+-------+
|  3   | 2016-06-06 |   5   |
|  8   | 2016-09-09 |   3   |
+------+------------+-------+

我的服务器设置是：

**MySQL**
Server: localhost via TCP/IP
Server version: 5.5.16
Protocol version: 10
User: root@localhost
MySQL charset: UTF-8 Unicode (utf8)

**Web server**
Apache/2.2.21 (Win32) mod_ssl/2.2.21 OpenSSL/1.0.0e php/5.3.8
MySQL client version: mysqlnd 5.0.8-dev - 20102224 - $Revision: 310735 $

我试过这个脚本，但不起作用：

SELECT *
FROM tbl_mysql
WHERE date IN (SELECT MAX(date) FROM tbl_mysql GROUP BY code)

如何更改脚本以在我的服务器版本上运行？ 谢谢！

【参考方案1】：

您可以申请自加入；

select t1.* from table1 t1 inner join 
(select code,max(date) maxDate from table1 group by code) t2
ON t1.code = t2.code and t1.date = t2.maxDate

Demo

【参考方案2】：

http://sqlfiddle.com/#!9/4cf933/2

SELECT t.*
FROM tbl_mysql t
LEFT JOIN tbl_mysql t2
ON t.code = t2.code
   AND t.date<t2.date
WHERE t2.id IS NULL