PHPSMARTY dual-loop (recursive) output classification problems

PHPSMARTY dual-loop (recursive) output classification question Template PHPcode {foreachfrom = $ classlistitem = newsclass} & lt; DIVclass = & quot; bg03 & quot; & gt; & lt; ahref = & quot; news. php? Classid = {$ newsclas php smarty dual-loop (recursive) output classification problem
Template

PHP code

  {foreach from=$classlist item=newsclass}    {$newsclass.classname}{/foreach}

Program

PHP code

  $sql = "select * from jh_newsclass where parentid = 0";$result = $mysqli->query($sql);while ($row = $result->fetch_row()) {    $classlist[] = array(        'id'=>$row[0],        'classname'=>$row[2],        'parentid'=>$row[1],        'ispro'=>$row[3],            );}$result->close();$mysqli->close();$smarty->assign('classlist',$classlist);$smarty->assign('webname',Webname);$smarty->display('admin/left.htm');

In this way, only the level-1 category can be output. I need to output level-2 under the level-1 category... how should I write?


Effects output by ASP in the past

HTML code

  News Topics
  
  

   
   
+ -- News
   
   
+ -- Major topics
   
   
+ -- Moon rabbit topic
  
  
Supply and demand information product display
  
  

   
   
+ -- U.S. cooker
   
   
+ -- Monthly graph Kitchen Cabinet
   
   
+ -- Integration effect
  
  

Original ASP code

HTML code

  <%dim strsSet Rs = server.CreateObject(JH_RS)sql = "select * from jh_newsclass where parentid = 0"Rs.Open SQL,Conn,1,1while not rs.eof%><%        set strs = conn.execute("select * from jh_newsclass where parentid = " & rs("id"))        if strs.eof and strs.bof then%>    &newsclass=<%=rs("id")%><%if rs("ispro") then response.Write("&ispro=true")%>" target="main"><%=rs("classname")%><%        else%>              <%=rs("classname")%><%        end if%>        <%call showparentclass("+","--",rs("id"))%><%rs.movenextwendrs.closeset rs = nothing%><%sub showparentclass(astr,tree,parentid)    dim showparentclassrs,temprs    set showparentclassrs = conn.execute("select * from Jh_newsclass where parentid = " & parentid)    if showparentclassrs.eof then         exit sub    else    response.Write("
  
  

   
   ")        while not showparentclassrs.eof            response.Write"
   
   
" set temprs = conn.execute("select * from Jh_newsclass where parentid = " & showparentclassrs("id")) if temprs.eof and temprs.bof then response.Write"" & astr & tree & "" & showparentclassrs("classname")&"" else response.Write astr & tree & "" & showparentclassrs("classname") end if set temprs = nothing response.Write"
"            call showparentclass(astr,tree&"--",showparentclassrs("id"))        showparentclassrs.movenext        wend    response.Write("
  
  
")    end ifend sub%>