mysql去除重复

今天在做个联系人功能时，要做导入去重复的功能
假设有10万个联系人，导入1万个，要把重复的去掉
想不到什么好的办法，只能把这1万个号码导入，然后再把重复的删掉

DELETE from telbook 
where id in 
(SELECT id 
FROM (
SELECT id from telbook
where Mobile in (SELECT b.Mobile from telbook b GROUP BY b.Mobile HAVING count(1)>1)
and id not in (SELECT MIN(c.ID) from telbook c GROUP BY c.Mobile HAVING count(1)>1) 
)v 
)