How to fetch counts from a query from a mongodb collection?

Question

I want to create a filter experience where I take filter criteria from request params and do the filtering of data using the mongo aggregation framework. Please suggest me a suitable approach.

Let the collection of data be like

        {
            "material": "silver",
            "type": "beads",
            "shape": "round",
            "_user": "5f9b78bf1130ca88e2e1d"
        },
        {
            "material": "mixed",
            "type": "jewels",
            "shape": "round",
            "_user": "5f9b78bf1130ca88e2e1d"
        },
        {
            "material": "gold",
            "type": "jewels",
            "shape": "other",
            "_user": "5fda2b717112437f9c06"
        },
        {
            "material": "silver",
            "type": "jewels",
            "shape": "other",
            "_user": "5f9b78bf1130ca88e2e1d"
        },
        {
            "material": "mixed",
            "type": "jewels",
            "shape": "other",
            "_user": "5fda2b717112437f9c706"
        },

Let the queried data be _user equals 5f9b78bf1130ca88e2e1d, material equals an array of silver, mixed, type equals an array of beads, jewels & shape equals an array of round

My query should return subsequent counts in each filter category(user, material, shape, type).

data = {
  categorizedByUser: [
    {
      _id: '5f9b78bf1130ca88e2e1d',
      count: 2
    },
    {
      _id: '5fda2b717112437f9c06',
      count: 0
    },
  ],
  categorizedByMaterial: [
    {
      _id: 'silver',
      count: 1
    },
    {
      _id: 'mixed',
      count: 1
    },
    {
      _id: 'gold',
      count: 0
    },
  ],
  categorizedByShape: [
    {
      _id: 'round',
      count: 2
    },
    {
      _id: 'other',
      count: 0
    },
  ]
  categorizedByType: [
    {
      _id: 'beads',
      count: 1
    },
    {
      _id: 'jewels',
      count: 1
    },
  ]
]

varman · Accepted Answer · 2021-01-20 07:09:11Z

1

You can use $facet to categorize incoming data

db.collection.aggregate([
  {
    $facet: {
      categorizedByUser: [
        {
          $group: {
            _id: "$_user",
            count: {
              $sum: 1
            }
          }
        }
      ],
      categorizedByMaterial: [
        {
          $group: {
            _id: "$material",
            count: {
              $sum: 1
            }
          }
        }
      ],
      categorizedByShape: [
        {
          $group: {
            _id: "$shape",
            count: {
              $sum: 1
            }
          }
        }
      ],
      categorizedByType: [
        {
          $group: {
            _id: "$type",
            count: {
              $sum: 1
            }
          }
        }
      ]
    }
  }
])

Working Mongo playground

answered Jan 20, 2021 at 7:09

varman

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1 Comment

Vivek Tiwari Over a year ago

Thanks !! Categorize the data is fine but how can I filter it based on the query. Let the query be, _user = 5f9b78bf1130ca88e2e1d material = [silver, mixed] type = [beads, jewels] shape = [round] Filter data => Categorization => Response

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