Laravel 有子查询的联合查询

$subSql=DB::table{(}^{\prime }bas{e}_{m}essag{e}^{\prime })->where($where)
->selectRaw(‘message_id,from_user_id,count(from_user_id) AS admin_no_reply_count’)
->groupBy(‘from_user_id’)
->orderBy(‘message_id’, ‘desc’)
->paginate(20);
$grid->model()->fromSub($subSql, ‘a’)
->join(‘base_message’,‘base_message.message_id’,‘a.message_id’)
->get();