Question

在下面的获取数据结果中：

{
    "purchases": [
        {
            "id": 1,
            "member_id": 1,
            "mediator_id": 2,
            "type": null,
            "cash": 38712402,
            "created_at": "2017-11-08 06:40:45",
            "updated_at": "2017-11-08 06:40:45",
            "deleted_at": null,
            "cheques": [
                {
                    "id": 1,
                    "purchase_id": 1,
                    "expire_date": "1396-01-19",
                    "amount": 97094060,
                    "isRejected": 0,
                    "created_at": "2017-11-08 06:40:45",
                    "updated_at": "2017-11-08 06:40:45",
                    "deleted_at": null
                }
            ]
        },
        {
            "id": 2,
            "member_id": 1,
            "mediator_id": 2,
            "type": null,
            "cash": 46760191,
            "created_at": "2017-11-08 06:40:45",
            "updated_at": "2017-11-08 06:40:45",
            "deleted_at": null,
            "cheques": []
        }
    ]
}

我通过这段代码得到了它：

$purchases = \App\Purchase::with('cheques')->where('member_id',
        $request->userId)->get();

我试图从amount cheques和'cash','created_at' purchases 'member_id'=$request->userId获取cheques，但我得空$purchases = \App\Purchase::with(array('cheques'=>function($query){ $query->select('amount'); }))->where('member_id',$request->userId)->get(['cash','created_at']);当我使用这段代码时：

{{1}}

Answer 1

你能试试吗？

$purchases = \App\Purchase::with(array('cheques'=>function($query){
    $query->select('id', 'amount', 'purchase_id');
}))->where('member_id',$request->userId)->get(['cash','created_at']);

Answer 2

尝试文档中的Eager Loading Specific Columns部分 - https://laravel.com/docs/5.5/eloquent-relationships

它说：

使用此功能时，您应始终在要检索的列列表中包含id列。

Answer 3

$purchases = \App\Purchase::with(
    array('cheques' => function($query){
        $query->select('amount');
    })
    )->where('member_id',$request->userId)
    ->select('cash','created_at')->get();

如果要使用get methon of collection选择列，则需要传递id：

->get(['id', 'cash', 'created_at']);或您可以使用->select('cash', 'created_at')->get();

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Laravel使用join来获取数据返回null

3 个答案: