Display multilevel subcategory of a category using single table

Today i am going to show all category and its sub-category by using a single table like below example -

My example table like below. In below table all the title which cat_id is '0' that are main category and rest of others are sub category to there parent id.

Now my requirement is to get all category with its subcategory in array .To fulfill this requirement i make a function getCategoryForParentId (parentId=0) like below -

x------------------x----------------x----------------------------------------------------------------------x

function getCategoryForParentId($parent_id = 0) {
$categories = array();
$sql = "SELECT id, cat_id, title FROM category WHERE cat_id='".$parent_id."' ORDER BY title asc";
$result = $this -> result_array($sql);

foreach ($result as $mainCategory) {
$category = array();
$category['id'] = $mainCategory['id'];
$category['name'] = $mainCategory['title'];
$category['parent_id'] = $mainCategory['cat_id'];
$category['sub_categories'] = $this->getCategoryForParentId($category['id']);
$categories[$mainCategory['id']] = $category;
}
return $categories;
}

x--------------------x---------------------------x--------------------------x------------------------------x


Above function return an array with related category and it's subcategory like below example array-

Array
(
    [43] => Array
        (
            [id] => 43
            [name] => ASTM
            [parent_id] => 3
            [sub_categories] => Array
                (
                )

        )

    [44] => Array
        (
            [id] => 44
            [name] => DIN
            [parent_id] => 3
            [sub_categories] => Array
                (
                    [50] => Array
                        (
                            [id] => 50
                            [name] => BS
                            [parent_id] => 44
                            [sub_categories] => Array
                                (
                                    [52] => Array
                                        (
                                            [id] => 52
                                            [name] => UNE
                                            [parent_id] => 50
                                            [sub_categories] => Array
                                                (
                                                )

                                        )

                                )

                        )

                    [49] => Array
                        (
                            [id] => 49
                            [name] => ISO
                            [parent_id] => 44
                            [sub_categories] => Array
                                (
                                    [51] => Array
                                        (
                                            [id] => 51
                                            [name] => GOST
                                            [parent_id] => 49
                                            [sub_categories] => Array
                                                (
                                                )

                                        )

                                )

                        )

                )

        )

)

Below is my html :

<div class="left_colom">
               <span class="categories_box"> Categories</span>
            <ul class="left_nav">
                <?php
                $categoryAll=$category->getCategory();
                if(!empty($categoryAll)){
                    foreach($categoryAll as $cat){
                        $subcat=$category->getCategoryForParentId($cat['id']);
                        echo "<pre>";
                        print_r($subcat);die;
                                           
                ?>
                <li <?=(!empty($subcat)) ? "id='category'" :""?>><a href="<?=(empty($subcat)) ? $BASE_PATH."product_list.php?catid=".$cat['id'] : "javascript:void()" ?>" title=""><?=$cat['title']?> </a>
                    <?php if(!empty($subcat)){?>
                    <ul style="display:none;" id="subcat">
                    <?php foreach($subcat as $subcatogry){?>
                    <li><a href="#" title=""><?=$subcatogry['name']?></a>
                        <?php if(!empty($subcatogry['sub_categories'])){?>
                        <ul>
                            <?php foreach($subcatogry['sub_categories'] as $subSubcat){?>
                            <li><a href="#" title="ISO"><?=$subSubcat['name']?></a>
                                <?php if(!empty($subSubcat['sub_categories'])){?>
                                <ul>
                                    <?php foreach($subSubcat['sub_categories'] as $subSubSubcat){?>
                                    <li><a href="#" title="GOST"><?=$subSubSubcat['name']?></a></li>
                                    <?php }?>
                                </ul>
                                <?php }?>
                            </li>
                            <?php }?>
                        </ul>
                        <?php }?>
                    </li>
                    <?php }?>
                    </ul>
                </li>
                <?php }} }else{
                    echo '<li><a href="javascript:void();" style="color:red;">Sorry no category found.</a></li>';
                  }
                ?>

            </ul>
</div>

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Happy coding :)