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How to get unique values from MongoDB collection?
To get unique values and ignore duplicates, use distinct() in MongoDB. The distinct() finds the distinct values for a specified field across a single collection and returns the results in an array.
Let us create a collection with documents −
> db.demo704.insertOne({"LanguageCode":"hi"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6ee18551299a9f98c93bd")
}
> db.demo704.insertOne({"LanguageCode":"en"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6ee1e551299a9f98c93be")
}
> db.demo704.insertOne({"LanguageCode":"hi"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6ee20551299a9f98c93bf")
}
> db.demo704.insertOne({"LanguageCode":"eo"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6ee2c551299a9f98c93c0")
}
> db.demo704.insertOne({"LanguageCode":"eu"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6ee2f551299a9f98c93c1")
}
> db.demo704.insertOne({"LanguageCode":"fo"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6ee35551299a9f98c93c2")
}
> db.demo704.insertOne({"LanguageCode":"fo"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6ee37551299a9f98c93c3")
}Display all documents from a collection with the help of find() method −
> db.demo704.find();
This will produce the following output −
{ "_id" : ObjectId("5ea6ee18551299a9f98c93bd"), "LanguageCode" : "hi" }
{ "_id" : ObjectId("5ea6ee1e551299a9f98c93be"), "LanguageCode" : "en" }
{ "_id" : ObjectId("5ea6ee20551299a9f98c93bf"), "LanguageCode" : "hi" }
{ "_id" : ObjectId("5ea6ee2c551299a9f98c93c0"), "LanguageCode" : "eo" }
{ "_id" : ObjectId("5ea6ee2f551299a9f98c93c1"), "LanguageCode" : "eu" }
{ "_id" : ObjectId("5ea6ee35551299a9f98c93c2"), "LanguageCode" : "fo" }
{ "_id" : ObjectId("5ea6ee37551299a9f98c93c3"), "LanguageCode" : "fo" }Following is the query to get unique values and display the result in an array −
> db.demo704.distinct("LanguageCode");This will produce the following output −
[ "hi", "en", "eo", "eu", "fo" ]
Updated on: 14-May-2020
15K+ Views
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