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Projection of one column in MongoDB?
Let us first create a collection with documents −
> db.demo216.insertOne({"ClientName":"John","ClientAge":34});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3e351003d395bdc213470c")
}
> db.demo216.insertOne({"ClientName":"Bob","ClientAge":32});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3e351703d395bdc213470d")
}
> db.demo216.insertOne({"ClientName":"Mike","ClientAge":35});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3e351c03d395bdc213470e")
}Display all documents from a collection with the help of find() method −
> db.demo216.find();
This will produce the following output −
{ "_id" : ObjectId("5e3e351003d395bdc213470c"), "ClientName" : "John", "ClientAge" : 34 }
{ "_id" : ObjectId("5e3e351703d395bdc213470d"), "ClientName" : "Bob", "ClientAge" : 32 }
{ "_id" : ObjectId("5e3e351c03d395bdc213470e"), "ClientName" : "Mike", "ClientAge" : 35 }Following is the query to project only a single column −
> db.demo216.find({},{_id:0,"ClientAge":0});This will produce the following output −
{ "ClientName" : "John" }
{ "ClientName" : "Bob" }
{ "ClientName" : "Mike" }
Updated on: 30-Mar-2020
103 Views
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