Too return a specific field, use the find() method in MongoDB. Let us first create a collection with documents −
> db.specificFieldDemo.insertOne({"FirstName":"John","LastName":"Doe"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cb8019a623186894665ae31")
}
> db.specificFieldDemo.insertOne({"FirstName":"John","LastName":"Smith"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cb801ab623186894665ae32")
}
> db.specificFieldDemo.insertOne({"FirstName":"David","LastName":"Miller"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cb801b3623186894665ae33")
}
> db.specificFieldDemo.insertOne({"FirstName":"Sam","LastName":"Williams"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cb801bf623186894665ae34")
}
Following is the query to display all documents from the collection with the help of find() method −
> db.specificFieldDemo.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cb8019a623186894665ae31"),
"FirstName" : "John",
"LastName" : "Doe"
}
{
"_id" : ObjectId("5cb801ab623186894665ae32"),
"FirstName" : "John",
"LastName" : "Smith"
}
{
"_id" : ObjectId("5cb801b3623186894665ae33"),
"FirstName" : "David",
"LastName" : "Miller"
}
{
"_id" : ObjectId("5cb801bf623186894665ae34"),
"FirstName" : "Sam",
"LastName" : "Williams"
}
Following is the query to return specific field. Here, we are returning the field “LastName” −
> db.specificFieldDemo.find({},{_id:0,LastName:1});
This will produce the following output −
{ "LastName" : "Doe" }
{ "LastName" : "Smith" }
{ "LastName" : "Miller" }
{ "LastName" : "Williams" }