How to perform recursive queries?

How to perform recursive queries? The name of my database table is aaa and the content is as follows. How do I recursively query the parent node?

USER PUSER
16
24 16
19 16
21 24
32 19

For example, if you check 32: is the row where 32 19 and 16 are located? That's what I wrote. What should I do?

$ Result = mysql_query ("select * from 'AAA' where user = '32' union all
Select h. *, h1. from 'AAA' h join result h1 on h. user = h1.Puser ", $ link );
$ Row = mysql_fetch_row ($ result );

Reply to discussion (solution)

You all know that recursive queries are required. Why didn't you do it?
Generally

function foo($id) {  $res = array();  $rs = mysql_query("select * from aaa where user='$id'");  if($row = mysql_fetch_assoc($rs)) {    $res[] = $row;    $res = array_merge($res, foo($row['puser']));  }  return $res;}

Search until puser is empty

$ids = array();function getuser($user){    global $ids;    $result=mysql_query("select * from `aaa` where user='".$user."'",$link);    $data=mysql_fetch_assoc($result);    if($data['puser']!=''){        $ids[] = $user;        getuser($data['puser']);    }}getuser(32);print_r($ids);

Thanks to the two great gods, we still need to use the function. I will study it. thank you to the two great gods.

Right. recursion means that the function calls itself.

Thank you!