The objective of projection is to select/show few fields of selected document. For example: One department has so many managers and with the different key skills. Assume department head wants to see list of manager's who have particular skill set but does not see irrelevant information like their permanent address, number of children etc.
Use command format to construct your query.
db.collection_name.find({ skill: "xyz" } , {name:1, children_details:0, salary_details:0})
