Bootstrap dropdown with php and databases

I see your issue. You're getting all the items without parent and give them the same function, which means they all get assigned a parent class.

Basically, you need to find the parents that have children and then assign the correct class to them. Like so:

<?php
  // Check if the child-query result is larger than 0
  if(mysqli_num_rows($cquery) > 0) {
    // Run your code for 'parents' here.
    <li class="dropdown">
    </li>
  } else {
    // Run your code for 'noparents' here.
    <li class="nodropdown">
    </li>
  }
?>

If I were you, I would also prepare the statements in clean PHP code, so you only have to call some variables in the HTML. This makes your code much more readable. In the below example, you have the database call and the transforming code all in one place. In case you change one, you'd probably have to change the other, so it makes sense. Also, if someone else looks at your code, they understand it much quicker.

<li class="dropdown">
    <a href="#" class="dropdown-toggle" data-toggle="dropdown" id="text">
        <?php echo $parent['kategorija']; ?><span class="caret"></span>
    </a>
    <ul class="dropdown-menu" role="menu">
        <?php echo get_dropdown_children(); ?>
    </ul>
<li>

<?php
function get_dropdown_children($parent['id']) {
    $sql2 = "SELECT * FROM categories WHERE parent = '$parent_id' ";
    $cquery = $db->query($sql2);
    $result = "";

    while($child = mysqli_fetch_assoc($cquery)) {
        $result .= "<li><a href='" . $child['adresas'] . "'>";  // Opening tags
        $result .= $child['kategorija'];                        // Content
        $result .= "</a></li>";                                 // Closing tags
    }

    return $result;
}