[{"company":"npcompany","department":[{"name":"it","employeeIds":["emp1","emp2","emp3"]},{"name":"economy","employeeIds":["emp1","emp3","emp4"]}]}]

db.collection.aggregate([{$unwind:"$department"},{"$match":{"department.employeeIds":"emp4"}},{$group:{"_id":"$_id",data:{"$push":"$$ROOT"}}}])