Get distinct values from each field within mongodb collection

Question

How to get the distinct values of all the fields within the mongodb collection using single query.

{ "_id": "1", "Gender": "male", "car": "bmw" , "house":"2bhk" , "married_to": "kalpu"},
{ "_id": "2", "Gender": "female", "car": nan , "house":"3bhk", "married_to": "kalpu"},
{ "_id": "3", "Gender": "female", "car": "audi", "house":"1bhk", "married_to": "deepa"},

This is an example with few fields, In my actual collection, each document has atleast 50 fields. So how to query effeciently that will return unique values within each of the fields? Thanks in advance for help.

Answer expected:

for each field,

  Gender:"male", "female"
  car   :"bmw", "audi",.....
  house : "3hbk","2bhk","1bhk"
  married_to: "kalpu","deepa",....
  ....
  ....
  ...

namar sood · Accepted Answer · 2020-08-26 10:08:11Z

2

You can use aggregation pipeline $group stage with $addToSet operator

db.collection.aggregate([
  {
    $group: {
      _id: null,
      Gender: {
        "$addToSet": "$Gender"
      },
      car: {
        "$addToSet": "$car"
      },
      house: {
        "$addToSet": "$house"
      },
      married_to: {
        "$addToSet": "$married_to"
      },
      
    }
  }
])

Working Example

answered Aug 26, 2020 at 10:08

namar sood

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3 Comments

namar sood Over a year ago

hey, did this answer your question ?

Induraj PR Over a year ago

Thanks, Yes it worked, But how to avoid "null" values being considered as distinct values.

namar sood Over a year ago

null values are considered the same

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