mongodb count num of distinct values per field/key

Question

Is there a query for calculating how many distinct values a field contains in DB.

f.e I have a field for country and there are 8 types of country values (spain, engl

Answer 1

To find distinct in field_1 in collection but we want some WHERE condition too than we can do like following :

db.your_collection_name.distinct('field_1', {WHERE condition here and it should return a document})

So, find number distinct names from a collection where age > 25 will be like :

db.your_collection_name.distinct('names', {'age': {"$gt": 25}})

Hope it helps!