laravel Eloquent 与 in with select 返回 null

Question

我使用 laravel eloquent 与关系，我有一个问题。

这些是我 Eloquent 模型；

class Post extends BaseModel
{

    public function user()
    {
        return $this->belongsTo(User::class, 'user_id', 'id');
    }

}


class User extends BaseModel 
{

    public function userInfo()
    {
       return $this->hasOne(UserInfo::class,'user_id','id');
    }
}


class UserInfo extends BaseModel
{


}

当我使用以下代码时，user_info 为空。

$posts = Post::with(['user' => function ($query) {
    $query->with(['userInfo' => function ($query) {
        $query->select(['nickname','avatar']);
    }]);
}])->paginate(10)
    ->toArray();

当我请求时，结果是

{
    "id": 10,
    "community_id": 1,
    "title": "biaoti",
    "desc": null,
    "content": "abc",
    "user_id": 1,
    "user": {
        "id": 1,
        "mobile_phone": "13800000003",
        "user_info": null
    }
}

但是下面的代码是正常的。

$posts = Post::with(['user' => function ($query) {
    $query->with(['userInfo' => function ($query) {
        // $query->select(['nickname','avatar']);
    }]);
}])->paginate(10)
    ->toArray();

当我请求它时，结果是:

{
    "id": 10,
    "community_id": 1,
    "title": "biaoti",
    "desc": null,
    "content": "abc",
    "user_id": 1,
    "user": {
        "id": 1,
        "mobile_phone": "13800000003",
        "user_info": {
            "id": 1,
            "user_id": 1,
            "nickname": "devkang",
            "avatar": "",
            "birthday": "1989-01-30",
            "sex": 1,
            "identity": 1,
            "region_id": 1
        }
    }
}

你能帮助我吗？我不知道如何使用它，我想从user_info中选择一些字段。

Answer 1

发生这种情况是因为您排除了 user_id使用时的外键 select方法。要修复它，将外键添加到列表中:

$query->select(['nickname', 'avatar', 'user_id']);