mysql去除重复数据

建立一张临时表

和原表一致的表结构

1	create table test_clear like test_dump;

自定义表结构，content_id标识原表中重复的字段

CREATE TABLE `test_clear` (
  `content_id` varchar(64) DEFAULT NULL,
  `maxId` bigint(20) DEFAULT NULL,
  UNIQUE KEY `uk_maxId` (`maxId`),
  KEY `nk_contentId` (`content_id`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC;

去重并插入临时表

1	insert into test_clear SELECT content_id,max(id) as maxId FROM test_dump GROUP BY content_id;

删除原表数据

1	DELETE FROM test_dump WHERE id not IN (SELECT maxId FROM test_clear)

其他方式

https://juejin.cn/post/6844903582114775053