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Get distinct levels of array field in MongoDB?
To get distinct levels of array field, use $addToSet in MongoDB. Let us create a collection with documents −
> db.demo122.insertOne({"ListOfValues":[100,10]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e2f20f1140daf4c2a3544b6")
}
> db.demo122.insertOne({"ListOfValues":[240,10]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e2f20f7140daf4c2a3544b7")
}Display all documents from a collection with the help of find() method −
> db.demo122.find();
This will produce the following output −
{ "_id" : ObjectId("5e2f20f1140daf4c2a3544b6"), "ListOfValues" : [ 100, 10 ] }
{ "_id" : ObjectId("5e2f20f7140daf4c2a3544b7"), "ListOfValues" : [ 240, 10 ] }Following is the query to get distinct levels of array field in MongoDB −
> db.demo122.aggregate([
... {
... "$group": {
... "_id": 0,
... "ListOfValues": { "$addToSet": "$ListOfValues" }
... }
... }
... ])This will produce the following output −
{ "_id" : 0, "ListOfValues" : [ [ 240, 10 ], [ 100, 10 ] ] }
Updated on: 31-Mar-2020
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