how to query fields withi a field inside mongo find query code example

Example 1: mongodb select specific fields

db.student.find({}, 'roll _id'); // <--- Just multiple fields name space separated
// OR
db.student.find({}).select('roll _id'); // <--- Just multiple fields name space separated
// OR
db.student.find({}, {'roll' : 1 , '_id' : 1 ); // <---- Old lengthy boring way

Example 2: mongodb select fields

db.inventory.find( { status: "A" }, { item: 1, status: 1 } )