mysql 删除重复项

之前爬虫写的逻辑有点错误，导致重复爬取了某些内容，全部删掉再爬也麻烦，所以写了个sql语句直接清掉重复项。

delete FROM tablename WHERE 去重字段 in 
(
	SELECT 去重字段
	FROM tablename 
	GROUP BY 去重字段 
	HAVING COUNT(*) > 1
) 
and id not in (
	select min(id) 
	from tablename 
	group by 去重字段 
	having count(*)>1
);