解决在laravel中leftjoin带条件查询没有返回右表为

DB::table('users as u')
  ->select('u.user_id','c.class')
  ->leftJoin('class as c','c.user_id','=','u.user_id')
  ->where('c.status','=',2)
  ->get();

select u.user_id,c.class from users u left join class c on u.user_id=c.user_id and c.status=2;

DB::table('users as u')
  ->select('u.user_id','c.class')
  ->leftJoin('class as c', function($join)
  {
    $join->on('c.user_id', '=', 'u.user_id')
    ->on('c.status', '=', '2');
  })
  ->get();