Why not display product in subcategory?

if($filter->filter_data=='category'){
			if(!($infoGet[0] == $filter->filter_namekey && count($infoGet) == 1)){
				$categoriesList='';
				foreach($infoGet as $cat){
					if($cat == $filter->filter_namekey || (int)$cat == 0)
						continue;

					if(is_numeric($cat)){
						$categoriesList.=(int)$cat.',';
					}elseif(is_string($cat)){
						$cat = explode('::',$cat);
						foreach($cat as $selectedCategory){
							$selectedCategory = trim($selectedCategory);
							if(!empty($selectedCategory))
								$categoriesList.=(int)$selectedCategory.',';
						}
					}
				}
				if(!empty($categoriesList)){
					$categoriesList=substr($categoriesList,0,-1);

					$table = 'a';
					if($a=='#__hikashop_product AS b'){
						$table = 'b';
					}elseif($a[0]!='(' && strpos($a,') AS b') && preg_match('#hikashop_product AS ([a-z0-9_]+)#i',$a,$matches)){
						$table = $matches[1];
					}
					$filter->filter_namekey = str_replace('-', '_', $filter->filter_namekey);
					$on.=' INNER JOIN '.hikashop_table('product_category').' AS '.$filter->filter_namekey.$i.' ON '.$filter->filter_namekey.$i.'.product_id='.$table.'.product_id AND '.$filter->filter_namekey.$i.'.category_id IN ('.$categoriesList.')';
				}
			}
		}