How to count and display additions to a tree in between date

[Nuv]

I made the basic function to count the number of left count and right count. However now i need to display then number of additions to a tree according to their joining date. I stuck here. can someone please show me the logic to do this ?

 

I know i need to use UNION for sql because date of joining and tree structure are in different tables.

 

Sql tables-

 

Member table -(doj is date of join)

 

Tree table-

 

Basic Code-

<?php 
function tree_count($node)   //Function to calculate count;$node is first lchild or first rchild.
  {
    $sql = "SELECT lchild,rchild FROM tree WHERE parent = '".$node."'" ;
// $sql = "SELECT lchild,rchild FROM tree WHERE parent = '".$node."'             should i do something like this ?
//           UNION SELECT member_id FROM member WHERE id_sponsor=".$node." AND doj BETWEEN '".$from."' AND '".$to."'" ;
    $execsql = mysql_query($sql);
    $array = mysql_fetch_array($execsql);
    
    if(!empty($array['lchild']))
    {
      $count += tree_count($array['lchild']);
      
    } 
    if(!empty($array['rchild']))
    {
       $count += tree_count($array['rchild']);
       
    }
    
    $totalcount = 1 + $count;
    return $totalcount;
    
  }  
?>