thinkphp5.1模型关联个field一起使用

$topics = MForum::field('id,title,time,reply,view,settop,choice,praise')->withJoin([
'forumcate' => [ 'id','name'],
'aliasofuser' => ['id','username','userhead']
])->where('open', 1)->order('settop desc,id desc')->paginate(1);