##### COMMAND TO SELECT THE DATABASE #####
> use office

##### COMMAND 1 #####
> db.employee.aggregate([ {"$match": { "emp_dept": "Technology" }}, {"$group": {"_id": {"emp_dept" : "$emp_dept"}, "No_of_Times": {"$sum": 1}}} ])

##### COMMAND 2 #####
> db.employee.aggregate([ {"$group": {"_id": {"emp_dept" : "$emp_dept"}, "Total_count_of_employees": {"$sum": 1}}} ])