cplb = request("cplb")
    sql = "select * from table where 1 = 1"
    if cplb <> "" then
        sql = sql & " and cplb = '"&cplb&"'"
    end if
    sql = sql & " order by id desc"

------解决方案--------------------

VBScript code

"SELECT * FROM Cp_biao WHERE cplb = ?"  
这个改下，如下

Dim strSql,strWhere
strWhere = "1=1"
If cplb<>"" Then
   strWhere =strWhere &"cplb="&cplb
End If
strSql = strSql&"strWhere"