如何使用聚合查询在 mongodb 中获取计数？

Question

I tried to get the count of Database using an aggregation query.

MY Scenrio

Access

[{
    "id": 1,
    name: 'laptop'
}, {
    "id": 2,
    name: 'deasktop'
}]

Query

db.access.aggregate([
    {
        $match: {}
    },
    {
        $group: {
            total: { $sum: 1 }
        }
    }
])

Exceute the query
I got the output

[{
    "total": 2
}]

Excepted output

{
    total: 1
    result: [{
        "id": 1,
        name: 'laptop'
    }, {
        "id": 2,
        name: 'deasktop'
    }]
}

How to get this output using aggregation query.

Answer 1

You need to $push your documents in $group stage

db.access.aggregate([
  {
    $match: {}
  },
  {
    $group: {
      _id: null,
      result: {
        $push: "$$ROOT"
      },
      total: {
        $sum: 1
      }
    }
  },
  {
    $project: {
      _id: 0
    }
  }
])

MongoPlayground

LINK $$ROOT