CODEWITHSUNDEEP
mongodbmongodb-queryaggregation-framework
艾瑪艾瑪艾瑪
艾瑪艾瑪艾瑪

Reputation: 310

How to add a particular value for all records in the collection using aggregation

How to add a particular value for all records in the collection using aggregation :

Have a collection with data :


[
 {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    present_working:true,
    age: 55,
    location: "texas",
    date:2019-11-25T01:00:00.000+00:00

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    location: "texas",
    date:2019-11-25T01:00:00.000+00:00
  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    location: "texas",
    date:2019-11-25T01:00:00.000+00:00

  }
]

if date column exists for any of the records present_working:true should be added in the collection for the records

expected output:


[
 {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    present_working:true,
    age: 55,
    location: "texas",
    date:2019-11-25T01:00:00.000+00:00

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    present_working:true,
    age: 45,
    location: "texas",
    date:2019-11-25T01:00:00.000+00:00
  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    present_working:true,
    age: 69,
    location: "texas",
    date:2019-11-25T01:00:00.000+00:00

  }
]

Upvotes: 1

Views: 50

Answers (2)

whoami - fakeFaceTrueSoul
whoami - fakeFaceTrueSoul

Reputation: 17925

So if you wanted to return conditionally add a field based upon existence of other field in aggregation while reading data from database then try below query :

/** If `date` exists then it will add the field & assign value to true else `$$REMOVE` will help to not add the field at all,
 * Additionally if you're ok to add this new field for docs where `date : null` then replace `$gt` with `$gte` */
db.collection.aggregate([
  {
    $addFields: {
      present_working: { $cond: [ { "$gt": [ "$date", null ] }, true, "$$REMOVE" ] }
    }
  }
])

Test : mongoplayground

Ref : aggregation-pipeline

Upvotes: 1

Viktor Simkó
Viktor Simkó

Reputation: 2637

There is no need to use aggregation for this.
You can do it simply this way:

collection.updateMany({
  date: {
    $exists: true
  }
}, {
  $set: {
    present_working: true
  }
})

If you want to do it with the aggregation framework:

collection.aggregate(
  [
    { 
      "$match" : {
        "date" : {
          $exists: true
        }
      }
    }, 
    { 
      "$addFields" : {
        "present_working" : true
      }
    }
  ]
)

Upvotes: 2

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