How to select a single field for all documents in a MongoDB collection?

Question

In my MongoDB, I have a student collection with 10 records having fields name and roll. One record of this collection is:

{
    \"         


        

Answer 1

db..find({}, {field1: , field2:  ...})

In your example, you can do something like:

db.students.find({}, {"roll":true, "_id":false})

Projection

The projection parameter determines which fields are returned in the matching documents. The projection parameter takes a document of the following form:

{ field1: , field2:  ... }

The  can be any of the following:

1. 1 or true to include the field in the return documents.

2. 0 or false to exclude the field.

NOTE

For the _id field, you do not have to explicitly specify _id: 1 to return the _id field. The find() method always returns the _id field unless you specify _id: 0 to suppress the field.

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