Delete from yourtable where yourfield not in (Select Min (Yourfield) from YourField Group by Field1, Field2)
Oh, anyway, download the open source file, what to send you! Http://www.zqdh.com.cn/incoming/mystun.rar please download it yourself, help me see if there is a problem. P.s: This is a Stun server and client for cross-bureaux network communication. People who are familiar with the network must try it :)