While loop returns only first row value

Question

For my tree category I use the below code, but there seems to be a problem, since it returns only the value of the 1st row:

<?php
function display_children($parent, $level) { 
    $result = mysql_query("SELECT * FROM `category` WHERE `parent`='$parent'"); 
    while ($row = mysql_fetch_array($result)) { 
        $title = $row['title'];
        $id = $row['id'];
        $results .= str_repeat('-> ',$level).$title;
        display_children($id, $level+1); 
    } 
    return $results;
}
display_children(0,0); 
?>

Any ideas what am I doing wrong and how to fix this?

Never ever put a query inside a loop, or even worse, inside a recursive function. There are 100 ways to do this better. — Peon
– Peon, Commented Nov 11, 2013 at 13:28

sg3s · Accepted Answer · 2013-11-11 13:25:22Z

2

I see you're not doing anything with your recursive function call return in there. Specifically I think you mean to also add those results to the $results variable...

Try this:

<?php
function display_children($parent, $level) { 
    $result = mysql_query("SELECT * FROM `category` WHERE `parent`='$parent'"); 
    $results = '';
    while ($row = mysql_fetch_array($result)) { 
        $title = $row['title'];
        $id = $row['id'];
        $results .= str_repeat('-> ',$level).$title;
        $results .= display_children($id, $level+1); 
    } 
    return $results;
}
echo display_children(0,0); 
?>

Additionally I declared the $results variable to prevent notices.

answered Nov 11, 2013 at 13:25

sg3s

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Comments

Alexander · Accepted Answer · 2013-11-11 13:26:43Z

2

Result of your function is lost. Replace:

$results .= str_repeat('-> ',$level).$title;
display_children($id, $level+1);

To:

$results .= str_repeat('-> ',$level).$title."\n".display_children($id, $level+1);

And at the end also display results:

echo display_children(0,0);

answered Nov 11, 2013 at 13:26

Alexander

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