laravel 子查询使用
$sql = DB::table('project')
->select('project_id','subject_id','user_id');
$join = DB::table('subject_info as si')
->joinSub($sql,'p',function($query){
$query -> on("p.subject_id","=","si.subject_id");
})
->leftJoin('member as m','m.id','=','p.user_id')
->select('p.*','si.subject_name','m.username')
->get();