Database
[{"Pharmacy":"a","EstablishedDate":ISODate("2006-10-12"),"Medicine":[{"MedName":"MedA","Quantity":55},{"MedName":"MedB","Quantity":34},{"MedName":"MedD","Quantity":25}]},{"Pharmacy":"b","EstablishedDate":ISODate("2015-02-02"),"Medicine":[{"MedName":"MedB","Quantity":60},{"MedName":"MedC","Quantity":34}]}]
Query
db.collection.aggregate([{$unwind:"$Medicine"},{$project:{"_id":0,"Medicine":"$Medicine.MedName","Pharmacy":"$Pharmacy"}}])