mysql删除冗余的数据库

-- 假设有一个表 `users`，其中 `email` 字段存在冗余数据
DELETE FROM users
WHERE id NOT IN (
    SELECT MIN(id)
    FROM users
    GROUP BY email
);

import mysql.connector

# 连接到MySQL数据库
db = mysql.connector.connect(
    host="localhost",
    user="yourusername",
    password="yourpassword",
    database="yourdatabase"
)

cursor = db.cursor()

# 删除冗余数据的SQL语句
sql = """
DELETE FROM users
WHERE id NOT IN (
    SELECT MIN(id)
    FROM users
    GROUP BY email
);
"""

# 执行SQL语句
cursor.execute(sql)

# 提交更改
db.commit()

# 关闭连接
cursor.close()
db.close()

START TRANSACTION;

DELETE FROM users
WHERE id NOT IN (
    SELECT MIN(id)
    FROM users
    GROUP BY email
)
LIMIT 1000;

COMMIT;

SET FOREIGN_KEY_CHECKS=0;

-- 执行删除操作

SET FOREIGN_KEY_CHECKS=1;

CREATE INDEX idx_email ON users(email);