mysql 多个字段重复的数据

ALTER TABLE table_name ADD UNIQUE INDEX idx_unique_field (field1, field2, ...);

INSERT IGNORE INTO table_name (field1, field2, ...) VALUES (value1, value2, ...);

REPLACE INTO table_name (field1, field2, ...) VALUES (value1, value2, ...);

INSERT INTO table_name (field1, field2, ...)
SELECT DISTINCT field1, field2, ...
FROM source_table;

UPDATE table_name
SET column_name = new_value
WHERE condition;

ALTER TABLE users ADD UNIQUE INDEX idx_unique_email_username (email, username);

INSERT IGNORE INTO users (email, username, password)
VALUES ('user@example.com', 'user123', 'password123');

INSERT INTO users (email, username, password)
SELECT DISTINCT email, username, password
FROM temp_users;