如何返回多对多关系的数据透视数据？

Question

如何为col1用户的角色选择数据透视数据（col2和id=2）？

+------------+
|    User    |
+------------+
| id | name  |
+----+-------+
| 1  | John  |
+----+-------+
| 2  | Brian |
+----+-------+

+------------+
|    Role    |
+------------+
| id | title |
+----+-------+
| 1  | Admin |
+----+-------+
| 2  | Owner |
+----+-------+

+-----------------------------------+
|              UserRole             |
+-----------------------------------+
| user_id | role_id |  col1 |  col2 |
+---------+---------+-------+-------+
|    2    |    1    | lorem | dolor |
+---------+---------+-------+-------+
|    2    |    2    | ipsum |  amet |
+---------+---------+-------+-------+

我可以使用User::find(2)->roles，但它会返回：

[
  {
    "id": 1,
    "title": "Admin",
    "pivot": {
      "user_id": 2,
      "role_id": 1,
      "col1": "lorem",
      "col2": "dolor"
    }
  },
  {
    "id": 2,
    "name": "Owner",
    "pivot": {
      "user_id": 2,
      "role_id": 2,
      "col1": "ipsum",
      "col2": "amet"
    }
  }
]

如何将查询更改为仅具有以下结果（仅限数据透视数据）：

[
  {
    "user_id": 2,
    "role_id": 1,
    "col1": "lorem",
    "col2": "dolor"
  },
  {
    "user_id": 2,
    "role_id": 2,
    "col1": "ipsum",
    "col2": "amet"
  }
]

Answer 1

您可以使用pluck()来实现此目标。

https://laravel.com/docs/5.3/collections#method-pluck

User::find(2)->roles->pluck('pivot');

希望这有帮助！