php mysql vertical menu

I am t开发者_如何学编程rying to design a dynamic vertical menu : my table is:

primary // primary key 
pid  //parent id 0 if none
cid //the actual category id
comment //some comment

the thing is that I want to design a php function where after reading the values from database it should output it into an html ordered list (like a multilevel nested unordered list) I know that it would be easily achieved by using a recursion function the problem is that i just can't do it.. I've tried many times but failed in vain The main problem comes in nesting (where to give list items and where to start the list)

I would be very grateful if anyone of you could help me out...

well i've managed to write an ugly code: {here i ve used two tables one for the parent and one for the child}

$query="SELECT * FROM parentCat";
$result=mysql_query($query);

echo "<ul id=\"suckertree1\">";

while($row=mysql_fetch_array($result))
{
    $name=$row['comment'];
    $pid=$row['catid'];
    echo "<li><a href=\"#\"> $name</a> ";
    $query="select * from childCat WHERE pid=$pid";
    $subresult=mysql_query($query);
    $af=mysql_num_rows($subresult);
    if($af>0)
    {
        echo "<ul>";

        while($subrow=mysql_fetch_array($subresult))
            {
                $name=$subrow['comment'];
                echo "<li><a href=\"#\"> $name</a> </li>";

            }
            echo "</ul>";
    }
    echo "</li>";
}
echo "</ul>";

it will show only one sublevel... wht should i do to make it work for infinite level

I thing a while script is best for you

$query = mysql_query("SELECT * FROM menu ORDER BY primary ASC");
$parent=0;
$sub=0
echo "<ul>";//start list
while($menu = mysql_fetch_array($query){
   if($parent != $menu['pid']){//if not seen item before
      if($sub != 0){echo "</ul>";}else{$sub++;}//if not first submenu, close submenu before. If first sub sub++.
      echo "<ul>";}//open submenu
   echo "<li>".$menu[cid]."</li>";//echo item
   if($parent != $menu['pid']){//if not seen before
      $parent = $menu['pid']; //set to seen before so next loop will be recognised
   }
}
echo "</ul>"; //end list

I dont know if this is gonna work since I did not test it, but it should show you an option on how it could be done. Idea of lists:

<ul>
  <li>Item1</li>
   <ul>
    <li>Subitem1</li>
    <li>Subitem2</li>
   </ul>
  <li>Item 2</li>
   <ul>
    <li>Subitem1 of Item2</li>
   </ul>
</ul>

Gives:

• Item1
• Subitem1
• Subitem2
• Item2
• Subitem1 of Item2

Try this, it should do the trick.

<?php

$query = "SELECT a.comment parent
               , b.comment child
          FROM menu a
          JOIN menu b
          ON a.primary = b.pid
          ORDER BY a.primary";

$result = mysql_query($query);
$parent = ''; 
echo "<ul>";
foreach ($result as $next) {
   if ($next['parent'] != $parent) {
      if (strlen($parent) > 0) {
         echo "    </ul>";
         echo "  </li>";
      }   
      echo "  <li>" . $next['parent'];
      echo "    <ul>";
   }   
   echo "    <li>" . $next['child'] . "</li>";

   $parent = $next['parent'];
}
echo "    </ul>";
echo "  </li>";
echo "</ul>";

?>

To render a nested list for an assoc array try this:

<?php
$list = array(
    'item-1' => 'test-1',
    'item-2' => 'test-2',
    'item-3' => array(
        'item-3-1' => 'test-3',
        'item-3-2' => array(
            'item-3-2-1' => 'test-4',
            'item-3-2-2' => 'test-5',
        ),
    ),
    'item-4' => 'test-6',
);

function render_list($list) {
    echo '<ul>';
    foreach ($list as $key => $value) {
        echo '<li>';
        echo $key.':';
        if (is_array($value)) render_list($value);
        else echo $value;
        echo '</li>';
    }
    echo '</ul>';
}

render_list($list);

Which will result in this:

<ul>
    <li>item-1:test-1</li>
    <li>item-2:test-2</li>
    <li>
        item-3:
        <ul>
            <li>item-3-1:test-3</li>
            <li>
                item-3-2:
                <ul>
                    <li>item-3-2-1:test-4</li>
                    <li>item-3-2-2:test-5</li>
                </ul>
            </li>
        </ul>
    </li>
    <li>item-4:test-6</li>
</ul>

• item-1:test-1
• item-2:test-2
• item-3:
  • item-3-1:test-3
  • item-3-2:
    • item-3-2-1:test-4
    • item-3-2-2:test-5
• item-4:test-6