加两个字段,一个是父ID,如果是顶层,父ID就为0,一个是是否有下级,0元1有,一个函数就可解决,在函数中间调用本函数,找出了父层,再找他是否有下级,如果有,再找父ID为本ID的栏目

'==================================================
'过程名：listecityclass
'作  用：显示系统分类
'参  数：id ------ 要匹配的系统ID
'==================================================
  Sub listecityclass(id)
    dim F_reco,F_total,F_n,F_classid,F_classname,F_classlayer
    set F_reco=Server.CreateObject("ADODB.Recordset")
    F_reco.Open "select classid,classname,classlayer from ws_ecityclass where classparent=0 and classlist=0 order by classorder Asc",conn,1,1
    F_total=F_reco.recordcount
    if F_total>0 then
      for F_n=1 to F_total
        format_i=1
    F_classid=F_reco(0)
    F_classname=F_reco(1)
    F_classlayer=F_reco(2)
        response.write "<option"
        if F_classlayer=0 then response.write " value=" & F_classid
        if id=F_classid then response.write " selected"
        response.write ">" & F_classname & "</option>"
        if F_classlayer=1 then call listecityclass_(id,F_classid)  '调用另一个函数,在下面
        F_reco.movenext
      next
    end if
    F_reco.close : set F_reco=nothing
  End Sub
  Sub listecityclass_(id,iid)
    dim F_reco,F_total,F_n,F_m,F_classid,F_classname,F_classlayer
    set F_reco=Server.CreateObject("ADODB.Recordset")
    F_reco.Open "select classid,classname,classlayer from ws_ecityclass where classparent="&iid&" and classlist=0 order by classorder Asc",conn,1,1
    F_total=F_reco.recordcount
    if F_total>0 then
      for F_n=1 to F_total
    F_classid=F_reco(0)
    F_classname=F_reco(1)
    F_classlayer=F_reco(2)
        format_i=format_i+1
        response.write "<option"
        if F_classlayer=0 then response.write " value=" & F_classid
        if id=F_classid then response.write " selected"
        response.write ">"
        for F_m=format_i to 2 step -1
          response.write "  "
          if F_m=2 then
            if F_n=F_total then response.write "└" else response.write "├"
      end if
        next
        response.write F_classname & "</option>"
        if F_classlayer=1 then call listecityclass_(id,F_classid) '调用本函数
        F_reco.movenext
        format_i=format_i-1
      next
    end if
    F_reco.close : set F_reco=nothing
  End Sub