【sql】MySQL删除某字段重复的数据，保留一条数据

1 DELETE FROM 表名 WHERE (字段1)
2 IN 
3 (SELECT 字段1 FROM (SELECT 字段1 FROM 表名 GROUP BY 字段1 HAVING COUNT(*)>1) s1) 
4 AND
5 id NOT IN (SELECT id FROM (SELECT id FROM account GROUP BY 字段1 HAVING COUNT(*)>1) s2);