Couchbase-从对象数组中选择字段的子集 [英] Couchbase - SELECT a subset of fields from array of objects

问题描述

我正在使用 travel-sample 数据集，并正在运行以下查询:

I am using the travel-sample data set, and am running the following query:

SELECT id, schedule FROM `travel-sample`WHERE type = "route" LIMIT 1;

它返回以下结果:

[
  {
    "id": 10000,
    "schedule": [
      {
        "day": 0,
        "flight": "AF198",
        "utc": "10:13:00"
      },
      {
        "day": 0,
        "flight": "AF547",
        "utc": "19:14:00"
      },
      ...
    ]
  }
]

但是，我不想返回 schedule.$.day 字段；即我希望我的结果是:

However, I don't want to return the schedule.$.day field; i.e. I want my results to be:

[
  {
    "id": 10000,
    "schedule": [
      {
        "flight": "AF198",
        "utc": "10:13:00"
      },
      {
        "flight": "AF547",
        "utc": "19:14:00"
      },
      ...
    ]
  }
]

如何仅从对象数组中选择对象字段的子集?

How can I SELECT only a subset of object fields from an array of objects?

我尝试了 UNNEST ，但是我不想为每个 schedule 元素单独记录-我希望将 schedule 元素保持嵌套在文档中.

I have tried UNNEST but I don't want to have a separate record for each schedule element - I want the schedule elements to remain nested inside the document.

我也尝试过使用 OBJECT_REMOVE

SELECT id, ARRAY OBJECT_REMOVE(x, 'day') FOR x in schedule END AS schedule FROM `travel-sample` WHERE type = "route" LIMIT 1;

但是我想将字段列入白名单而不是黑名单.

But I want to whitelist rather than blacklist fields.

推荐答案

您上一次尝试已结束.不用使用 OBJECT_REMOVE ，您只需构造要返回的对象即可.

Your last attempt was close. Instead of using OBJECT_REMOVE, you can simply construct the object you want returned.

SELECT id, ARRAY {"flight": x.flight, "utc": x.utc} FOR x in schedule END AS schedule FROM `travel-sample` WHERE type = "route" LIMIT 1;

您将获得以下结果:

[
  {
    "id": 10000,
    "schedule": [
      {
        "flight": "AF198",
        "utc": "10:13:00"
      },
      {
        "flight": "AF547",
        "utc": "19:14:00"
      },
      ...
    ]
  }
]

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