Laravel-如何合并查询

有两种模型BoardArticle和BoardArticleLocation

$articles = BoardArticle::where('board_id', $board_id)
    ->orderBy("id", 'desc')
    ->paginate(20);

这就是我尝试的方法

$articles = BoardArticle::where('board_id', $searchKey, $board_id)
    ->select('board_articles.*')
    ->addselect(DB::raw('CONCAT("[", group_concat(DISTINCT location_top_text), "]") as location_text'))
    ->leftjoin('board_article_locations', 'board_articles.id', '=', 'board_article_locations.board_article_id')
    ->groupby('board_articles.id')
    ->orderBy("id", 'desc')
    ->paginate(20);

这个方法太慢了

$articles = BoardArticle::where('board_id', $searchKey, $board_id)
    ->with('BoardArticleLocations')
    ->orderBy("id", 'desc')
    ->paginate(20);

Models\BoardArticleLocation
public function BoardArticleLocations()
    {
        return $this->hasMany(BoardArticleLocation::class)
            ->select('location_top as top', 'location_top_text as text')
            ->addselect(DB::raw('CONCAT("[", group_concat(location_sub), "]") as sub'))
            ->groupby('location_top');
    }

此方法未查找任何项

我该怎么办

$articles = BoardArticle::where('board_id', $searchKey, $board_id)
    ->with('BoardArticleLocations')
    ->orderBy("id", 'desc')
    ->paginate(20);

Models\BoardArticleLocation
public function BoardArticleLocations()
    {
        return $this->hasMany(BoardArticleLocation::class)
            ->select('location_top as top', 'location_top_text as text')
            ->addselect(DB::raw('CONCAT("[", group_concat(location_sub), "]") as sub'))
            ->groupby('location_top');
    }