arangodb - 无法从数据集中提取对象值以进行比较或应用过滤器

Question

我正在尝试解决此页面上的 Q.22 。数据集在这里

Q.22 编写一个 MongoDB 查询来查找在许多调查日期中在 ISODate "2014-08-11T00:00:00Z" 上获得“A”级和得分 11 的餐厅的餐厅 ID、名称和等级

数据格式如下：

[
  {
    "_key": "2451925",
    "_id": "restaurants/2451925",
    "_rev": "_buC4Kd2---",
    "address": {
      "building": "1007",
      "coord": [
        -73.856077,
        40.848447
      ],
      "street": "Morris Park Ave",
      "zipcode": "10462"
    },
    "borough": "Bronx",
    "cuisine": "Bakery",
    "grades": [
      {
        "date": {
          "$date": 1393804800000
        },
        "grade": "A",
        "score": 2
      },
      {
        "date": {
          "$date": 1378857600000
        },
        "grade": "A",
        "score": 6
      },
      {
        "date": {
          "$date": 1358985600000
        },
        "grade": "A",
        "score": 10
      },
      {
        "date": {
          "$date": 1322006400000
        },
        "grade": "A",
        "score": 9
      },
      {
        "date": {
          "$date": 1299715200000
        },
        "grade": "B",
        "score": 14
      }
    ],
    "name": "Morris Park Bake Shop",
    "restaurant_id": "30075445"
  },
  {
    "_key": "2451926",
    "_id": "restaurants/2451926",
    "_rev": "_buC4Kd2--A",
    "address": {
      "building": "469",
      "coord": [
        -73.961704,
        40.662942
      ],
      "street": "Flatbush Avenue",
      "zipcode": "11225"
    },
    "borough": "Brooklyn",
    "cuisine": "Hamburgers",
    "grades": [
      {
        "date": {
          "$date": 1419897600000
        },
        "grade": "A",
        "score": 8
      },
      {
        "date": {
          "$date": 1404172800000
        },
        "grade": "B",
        "score": 23
      },
      {
        "date": {
          "$date": 1367280000000
        },
        "grade": "A",
        "score": 12
      },
      {
        "date": {
          "$date": 1336435200000
        },
        "grade": "A",
        "score": 12
      }
    ],
    "name": "Wendy'S",
    "restaurant_id": "30112340"
  }]

我正在尝试使用上面给定的 ISODate 过滤掉日期。我正在使用 date_timestamp 函数将上述内容转换为日期在数据中的存储方式。

我无法过滤日期，因为它们似乎包含在 {"$date":1393804800000} 中。在 g 中尝试循环表示找到了一个对象，而不是一个集合或数组。应用过滤器并使用 date_timestamp() 检查相等性返回空值数组 []、[] 等。

for r in restaurants
    for g in r.grades
       let d=date_timestamp("2014-08-11T00:00:00Z")
       return {date:g.date,target_date:d}

请帮忙，谢谢

标签： arangodbaql

Answer 1

您必须过滤对象内的字段：

LET target_date = DATE_TIMESTAMP('2014-08-11T00:00:00Z')
FOR r IN restaurants
  FOR g IN r.grades
    FILTER g.date.$date == target_date
    RETURN {date: g.date}