MySQL删除重复数据中ID较大的数据

2024-01-23 15:57:55 浏览数 (1)

背景

数据库中，不小心插入了重复的数据，想删除多出来的

测试数据

代码语言：javascript复制

CREATE TABLE user (
  id INT PRIMARY KEY,
  username VARCHAR(255)
);

INSERT INTO user (id, username) VALUES
(1, 'zhangsan'),
(2, 'lisi'),
(3, 'zhangsan'),
(4, 'lisi'),
(5, 'wangwu'),
(6, 'zhaoliu'),
(7, 'zhaoliu');

筛选指定重复数据中ID较大的数据

代码语言：javascript复制

SELECT max(id), username
FROM user where username in ('zhangsan','lisi')
GROUP BY username;

删除重复的数据

代码语言：javascript复制

DELETE FROM user WHERE id IN (
    SELECT id
        FROM (
            SELECT max(id) as id
            FROM user where username in ('zhangsan','lisi')
            GROUP BY username
    ) as subquery
);

mysql select 数据数据库 max

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