recursion function problem..........

I want find out the parent category id which category id is 0 ????????????????
my table :
id name p_id
1 hotels 0
2 food 1
3 lunch 2

function find_pid($val)
   {
   $sqlfetch = mysql_query("select * from category_tb where id = '{$val}'");
   $refetch = mysql_fetch_array($sqlfetch);
   if($refetch['p_id'] > 0)
     {
       find_pid($refetch['p_id']);
     }
   else
     {
       $cat = $refetch['id'];
       return $cat;
     }
   }

echo find_pid(3);

PHP:

but here result is not display...................
plz tell me what the problem, plz help me....................

 

Try this

function find_pid($val)
{
    $sqlfetch = mysql_query("select * from category_tb where id = '".$val."'");
    while ($row = mysql_fetch_array($sqlfetch)) {
        if ($row['p_id'] == 0)
        {
            return $row['p_id']);
        }
    }
    return "failed to find a result with p_id == 0";
}

PHP:

 

Hello,
Your script doing several queries into database, it is not a good idea. You may make this with just a single query.

SELECT t.id, t.name, @pv := t.p_id as p_id
FROM (SELECT * FROM category_tb ORDER BY id DESC) t
JOIN (SELECT @pv := YOUR_VAL_HERE) tmp
WHERE t.id = @pv

Code (markup):

You will get several rows (full path) where the last one will be your parent element

 

Ah, I think what Sano000 is trying to say is that you could solve this with a much simpler query and just skip the loop and recursion like this

$sqlfetch = mysql_query("SELECT * FROM category_tb WHERE id = '".$val."' AND p_id = 0");

Code (markup):

This will give you all the rows that have your value and and have a p_id equal to 0

 

No, I trying to say, that you can make a recursivity on a Mysql server side. It will be faster and easier. Just add my query into mysql_query function and pop a last row.

 

how about this?

function find_pid($val)
{
$sqlfetch = mysql_query("select * from category_tb where id = '{$val}'");
$refetch = mysql_fetch_array($sqlfetch);
if($refetch['p_id'] > 0)
{
return find_pid($refetch['p_id']);
}
else
{
$cat = $refetch['id'];
return $cat;
}
}

PHP:

​

 

thanks for reply....