[{"message":"Get Order Successfully","result":[{"_id":"5ff47348db5f5917f81871aa","productDetail":[{"name":"Camera","productImage":[{"_id":"5fe9b8a26720f728b814e246","img":"uploads\\product\\7Rq1v-app-7.jpg"},{"_id":"5fe9b8a26720f728b814e247","img":"uploads\\product\\FRuVb-app-8.jpg"}],"price":550}]}]}]

db.collection.aggregate([{"$unwind":"$result"},{"$unwind":"$result.productDetail"},{$project:{pImage:{"$first":"$result.productDetail.productImage"}}}])