SQL按照某一列数据去重并显示整行信息

1.0 创建测试

CREATE TABLE `logtest` (
    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
    `msg` varchar(500) NOT NULL,
    `create_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
    `update_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    PRIMARY KEY (`id`)
)ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
insert into `logtest` (msg) values(‘bbbbbbbbbbbbb‘);
select * from logtest;

1.1 表中所有数据

vGroup by和Max写法

需求背景

按照时间升序在日志表中取出不msg不重复的前3条数据

select * from logtest
where id in (select Max(id) from logtest group by msg)
order by create_time asc limit 3;

SQL按照某一列数据去重并显示整行信息

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