N

Post::where('status', 1)
    ->join('post_tag', 'posts.id', '=', 'post_tag.post_id')
    ->join('tags', 'tags.id', '=', 'post_tag.tag_id')
    ->select('posts.*', DB::raw('group_concat(tags.name) as tags_name'))
    ->groupBy('posts.id', 'posts.name', 'posts.content')->get();

Post::where('status', 1)
    ->select('posts.*', DB::raw('select group_concat(tags.name) as tags_name from post_tag join tags on tags.id=post_tag.tag_id where post_tag.post_id = posts.id'))->get();

The enctype attribute can be used only if method="post".

SELECT name, `text`
FROM product
JOIN product_attribute USING (product_id)
JOIN attribute_description USING (attribute_id)
-- JOIN attribute USING (attribute_id)   -- таблица в запросе не нужна
GROUP BY 1, 2
HAVING COUNT(*) > 1;

class ResponseObject
{
    public static function parse(object $data): ResponseObject1|ResponseObject2|ResponseObject3|ResponseObject4
    {
        switch ($data->type) {
            case 'type1':
                return new ResponseObject1($data);
            case 'type2':
                return new ResponseObject2($data);
            case 'type3':
                return new ResponseObject3($data);
            case 'type4':
                return new ResponseObject4($data); 
        }
    }
}

SELECT *
  FROM `posts`
  WHERE `id` IN (
    SELECT `id_post`
      FROM `tags_rel`
      WHERE `id_tag` IN (1,2,3)
    ) AND `status` = 1
  LIMIT 0, 50