MongoDB Documentation, Release 3.0.4 Projections, which are the second argument to the find() method, may either specify a list of fields to return or list fields to exclude in the result documents. Important: Except for excluding the _id field in inclusive projections, you cannot mix exclusive and inclusive projections. Consider the following diagram of the query process that specifies a query criteria and a projection: In the diagram, the query selects from the users collection. The criteria matches the documents that have age equal to 18 . Then the projection specifies that only the name field should return in the matching documents. db.records.find( { "user_id": { $lt: 42 } }, { "history": 0 } ) db.records.find( { "user_id": { $lt: 42 } }, { "name": 1, "email": 1 } ) This query selects documents in the records collection that match the query { "user_id": { $lt: 42 } } and uses the projection { "name": 1, "email": 1 } to return just the _id field (implicitly included), name field, and the email field in the documents in the result set. Return Two fields and the _id Field This query selects documents in the records collection that match the condition { "user_id": { $lt: 42 } } , and uses the projection { "history": 0 } to exclude the history field from the documents in the result set. Projection Examples Exclude One Field From a Result Set 63 3.2. MongoDB CRUD Concepts