asp+sql select 下拉框内无法显示表zxg的值

<select name="select">
<option value="">请选择</option>
<%
set conn=server.createobject("adodb.connection")
conn.Open "DSN=mysql;UID=sa;PWD=sa;Database=code"

set rs=conn.execute("select * from zxg")
do while not rs.eof
%>
<option value=<%=rs("zxgid")%><%=rs("zxgid")%></option>
<%
rs.movenext
loop
rs.close
set rs=nothing
%>
</select>
请高手指教