List all values of a certain field in mongodb
MongodbMongodb QueryDatabaseMongodb Problem Overview
How would I get an array containing all values of a certain field for all of my documents in a collection?
db.collection:
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be6"), "x" : 1 }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be7"), "x" : 2 }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be8"), "x" : 3 }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be9"), "x" : 4 }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990bea"), "x" : 5 }
"db.collection.ListAllValuesForfield(x)" Result: [1,2,3,4,5]
Also, what if this field was an array?
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be6"), "y" : [1,2] }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be7"), "y" : [3,4] }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be8"), "y" : [5,6] }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be9"), "y" : [1,2] }
{ "_id" : ObjectId("51a7dc7b2cacf40b79990bea"), "y" : [3,4] }
"db.collection.ListAllValuesInArrayField(y)" Result: [1,2,3,4,5,6,1,2,3,4]
Additionally, can I make this array unique? [1,2,3,4,5,6]
Mongodb Solutions
Solution 1 - Mongodb
db.collection.distinct('x')
should give you an array of unique values for that field.
Solution 2 - Mongodb
This would return an array of docs, containing just it's x value...
db.collection.find(
{ },
{ x: 1, y: 0, _id:0 }
)
Solution 3 - Mongodb
Notice: My answer is a fork from the original answer.
Before any "thumbs up" here, "thumbs up" the accepted answer :).
db.collection.distinct("NameOfTheField")
> Finds the distinct values for a specified field across a single collection or view and returns the results in an array.
Reference: https://docs.mongodb.com/manual/reference/method/db.collection.distinct/