Multiple queries in one model function

Code:

function categories()

    {

        $this->load->database('database_name', TRUE);

        $this->db->select('category');

        $this->db->group_by('category');

        $query = $this->db->get('table');

        

        foreach ($query->result() as $categories)

        {

            $categories_array[] = $categories;

        }

        return $categories_array;

    }

Code:

function sub_categories()

    {

        $this->load->database('database_name', TRUE);

        $this->db->select('sub_category');

        $this->db->where('category',$categories);

        $query = $this->db->get('table');

        

        foreach ($query->result() as $sub_categories)

        {

            $sub_categories_array[] = $sub_categories;

        }

        return $sub_categories_array;

    }

Code:

$blah['categories'] = $categories_array;

$blah['sub_categories'] = $sub_categories_array;

return $blah;

Code:

$select_categories = "SELECT category FROM ms_artworks.artworks GROUP BY category";

$query_categories = mysql_query($select_categories) or die(mysql_error());

$row_select_categories = mysql_fetch_assoc($query_categories);

$totalrows_select_categories = mysql_num_rows($query_categories);



<ul class="menu">

&lt;?php do { ?&gt;

    <li class="category">&lt;?php echo $row_select_categories['category'];

    $category = $row_select_categories['category'];

    $select_sub_categories = "SELECT sub_category FROM ms_artworks.artworks WHERE category = '$category'";

    $query_sub_categories = mysql_query($select_sub_categories, $connection_ms_catalog) or die(mysql_error());

    $row_select_sub_categories = mysql_fetch_assoc($query_sub_categories);

    $totalrows_select_sub_categories = mysql_num_rows($query_sub_categories);?&gt;</li>

    &lt;?php do { ?&gt;

        <li class="sub_category"><a href="&lt;?php echo $row_select_sub_categories['sub_category'];?&gt;">&lt;?php echo $row_select_sub_categories['uk'];?&gt;</a> </li>

        &lt;?php } while ($row_select_sub_categories = mysql_fetch_assoc($query_sub_categories)); ?&gt;

        &lt;?php } while ($row_select_categories = mysql_fetch_assoc($query_categories)); ?&gt;

        <li class="category">Logos &amp; Guides</li>

            <li class="sub_category"><a href="logos.php">Logos</a></li>

            <li class="sub_category"><a href="guides.php">Guides</a></li>

            </ul>