mysql表数据去重

DELETE t1 FROM table_name t1
LEFT JOIN (
    SELECT column_name, MIN(id) as min_id
    FROM table_name
    GROUP BY column_name
    HAVING COUNT(*) > 1
) t2 ON t1.column_name = t2.column_name AND t1.id = t2.min_id
WHERE t2.min_id IS NULL;

DELETE t1 FROM table_name t1
LEFT JOIN (
    SELECT column1, column2, MIN(id) as min_id
    FROM table_name
    GROUP BY column1, column2
    HAVING COUNT(*) > 1
) t2 ON t1.column1 = t2.column1 AND t1.column2 = t2.column2 AND t1.id = t2.min_id
WHERE t2.min_id IS NULL;

CREATE TEMPORARY TABLE temp_table AS
SELECT column1, column2, MIN(id) as min_id
FROM table_name
GROUP BY column1, column2;

DELETE FROM table_name
WHERE id NOT IN (SELECT min_id FROM temp_table);

DROP TEMPORARY TABLE temp_table;