MongoDB 聚合 - 从文档中的对象数组进行 $lookup 管道查询并匹配到单独集合文档的对象数组列表

Question

游乐场链接： 蒙戈游乐场

我想得到以下查询结果。

一张与

filters

开始匹配的卡片，它以字符串数组开始，以来自 filters 集合的新对象结束。

filters 集合有一个带有

enabled

和

archived

字段的主过滤器以及子过滤器列表。 CARD 过滤器

[string]

列表只会有子过滤器字符串值启动，但这些值可能来自多个主过滤器列表（子过滤器值）。

  "cards": [
    {
      "cardId": "one-two-three",
      "filters": [
        "one",
        "two",
        "five"
      ]
    }
  ],
  "filters": [
    {
      "label": "filter-one-primary",
      "enabled": true,
      "archived": false,
      "list": [
        {
          "label": "One",
          "value": "one",
          "disabled": false
        },
        {
          "label": "Four",
          "value": "four",
          "disabled": false
        }
      ]
    },
    {
      "label": "filter-two-primary",
      "enabled": true,
      "archived": false,
      "list": [
        {
          "label": "Two",
          "value": "two",
          "disabled": false
        },
        {
          "label": "Five",
          "value": "five",
          "disabled": false
        }
      ]
    }
  ]

例如，在上面的数据集中，一张卡片可能有一个以

filters

开头的

['one', 'two', 'five']

数组。

我希望在管道的开始部分首先根据主过滤器对象

"enabled": true

和

"archived": false

以及列表是否包含任何子过滤器来选择所有需要的过滤器。所以在上面的数据集中，它会选择两者。

获得过滤器后，我们需要将它们转换为第一个返回的 CARD 中的以下内容。

所以使用上面的例子，返回的CARD会有这个。

[
  {
    "_id": ObjectId("5a934e000102030405000000"),
    "cardId": "one-two-three",
    "filters": [
        {
            primary: "filter-one-primary", // Used to be from filter object.label
            secondary: "One", // Used to be from filter object.[list].value
            id: "one", // Used to be from filter object.[list].value
            disabled: false // Used to be from filter object.[list].disabled
        },
            primary: "filter-two-primary", // Used to be from filter object.label
            secondary: "Two", // Used to be from filter object.[list].value
            id: "two", // Used to be from filter object.[list].value
            disabled: false // Used to be from filter object.[list].disabled
        },
        {
            primary: "filter-two-primary", // Used to be from filter object.label
            secondary: "Five", // Used to be from filter object.[list].value
            id: "five", // Used to be from filter object.[list].value
            disabled: false // Used to be from filter object.[list].disabled
        }
    ]
  }
]

在

$lookup

管道中，我们将匹配：

// DATA

db={
  "cards": [
    {
      "cardId": "one-two-three",
      "filters": [
        "four",
        "five",
        "six"
      ]
    }
  ],
  "filters": [
    {
      "label": "filter-one-primary",
      "enabled": true,
      "archived": false,
      "list": [
        {
          "label": "One",
          "value": "one",
          "disabled": false
        },
        {
          "label": "Four",
          "value": "four",
          "disabled": false
        }
      ]
    },
    {
      "label": "filter-two-primary",
      "enabled": true,
      "archived": false,
      "list": [
        {
          "label": "Two",
          "value": "two",
          "disabled": false
        },
        {
          "label": "Five",
          "value": "five",
          "disabled": false
        }
      ]
    },
    {
      "label": "filter-three-primary",
      "enabled": true,
      "archived": false,
      "list": [
        {
          "label": "Three",
          "value": "three",
          "disabled": false
        },
        {
          "label": "SiX",
          "value": "six",
          "disabled": false
        }
      ]
    }
  ]
}
db.cards.aggregate([
  {
    $match: {
      "cardId": "one-two-three"
    }
  },
  {
    $lookup: {
      from: "filters",
      "let": {
        "id": "filters"
      },
      pipeline: [
        {
          $match: {
            $and: [
              {
                $expr: {
                  $in: [
                    "$$id",
                    "$list.value"
                  ]
                },
                "enabled": true,
                "archived": false
              }
            ]
          }
        }
      ],
      as: "filters"
    }
  }
])

Answer 1

在您的

$lookup

管道中：

1. $match

   - 您的

   $$id

   是来自

   filters

   数组值的数组字段。因此，您不应使用

   $in

   运算符，而应使用

   $setIntersection

   、

   $size

   运算符来检查数组之间是否存在任何相交/匹配的元素。

2. $unwind

   - 将

   list

   数组解构为多个文档。

3. $match

   - 通过匹配

   list.value

   来过滤文档。

4. $project

   - 装饰要在

   filters

   数组中输出的文档。

db.cards.aggregate([
  {
    $match: {
      "cardId": "one-two-three"
    }
  },
  {
    $lookup: {
      from: "filters",
      "let": {
        "id": "$filters"
      },
      pipeline: [
        {
          $match: {
            $and: [
              {
                $expr: {
                  $gt: [
                    {
                      $size: {
                        $setIntersection: [
                          "$$id",
                          "$list.value"
                        ]
                      }
                    },
                    0
                  ]
                },
                "enabled": true,
                "archived": false
              }
            ]
          }
        },
        {
          $unwind: "$list"
        },
        {
          $match: {
            $expr: {
              $in: [
                "$list.value",
                "$$id"
              ]
            }
          }
        },
        {
          $project: {
            _id: 0,
            primary: "$label",
            secondary: "$list.label",
            id: "$list.value",
            disabled: "$list.disabled"
          }
        }
      ],
      as: "filters"
    }
  }
])

演示@Mongo Playground