大神帮我看一下这段代码吧， 查找写入数据库的问题！

<!-- #include file="conn.asp" -->
<%   
     dim user,pwd,username,tel,msg1,msg2,msg3
     user=request.Form("user")
     pwd=request.Form("pwd")
     username=request.Form("username")
     tel=request.Form("tel")
     msg1="<script language=JavaScript>alert('用户名或密码不能为空!');javascript:history.go(-1)</script>"
     msg2="<script language=JavaScript>alert('注册成功!')</script>"
     msg3="<script language=JavaScript>alert('该用户已经被注册!';javascript:history.go(-1))</script>"
     if user="" or pwd="" or username="" or tel="" then
     response.Write(msg1)
     end if
     dim rs,sql
     set rs=server.CreateObject("ADODB.recordset")
         sql="select User from login where user"
         rs.open sql,conn,1,1
     if rs.recordcount=-1 then
       rs.open login,conn,1,3
       rs.addnew
       rs(User)=user
       rs(PWD)=pwd
       rs(UserName)=username
       rs(TEL)=tel
       rs.update
       rs.close
       set rs=nothing
       conn.nothing
       response.Write(msg2)
       else
       response.Write(msg3)
       end if
      
      
      
%>