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Find MongoDB document with array containing the maximum occurrence of a specific value
For this, you can use aggregate(). Let us first create a collection with documents −
> db.countOccurrencesDemo.insertOne({"ListOfValues":[65,87,89,65,67,87,87,87]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e06ef9325ddae1f53b621eb")
}
> db.countOccurrencesDemo.insertOne({"ListOfValues":[102,65,87,65,89,65,89,65,89,65]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e06efaa25ddae1f53b621ec")
}Following is the query to display all documents from a collection with the help of find() method −
> db.countOccurrencesDemo.find();
This will produce the following output −
{ "_id" : ObjectId("5e06ef9325ddae1f53b621eb"), "ListOfValues" : [ 65, 87, 89, 65, 67, 87, 87, 87 ] }
{ "_id" : ObjectId("5e06efaa25ddae1f53b621ec"), "ListOfValues" : [ 102, 65, 87, 65, 89, 65, 89, 65, 89, 65 ] }Here is the query to find document with array containing the maximum occurrence of a specific value −
> db.countOccurrencesDemo.aggregate(
... [
... { "$project": {
... "ListOfValues": 1,
... "OccurencesValue": {
... "$size": {
... "$filter": {
... "input": "$ListOfValues",
... "as": "v",
... "cond": { "$eq": [ "$$v", 65] }
... }
... }
... }
... }},
... { "$group": {
... "_id": "$OccurencesValue",
... "MyValues": { "$push": "$$ROOT" }
... }},
... { "$sort": { "_id": -1 } },
... { "$limit": 1 }
... ]
... );This will produce the following output −
{ "_id" : 5, "MyValues" : [ { "_id" : ObjectId("5e06efaa25ddae1f53b621ec"), "ListOfValues" : [ 102, 65, 87, 65, 89, 65, 89, 65, 89, 65 ], "OccurencesValue" : 5 } ] }
Updated on: 31-Mar-2020
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