mongodb only select certain fields 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: get only some fields of document in mongodb

db.student.find({}, {roll:1, _id:0})
 same as SELECT roll FROM student