db={"business":[{"_id":{"$oid":"60a34c76d8b10300111325ea"},"services":[{"$oid":"60a34da258d8b50011859c4d"},{"$oid":"60a34dc7d8b10300111325f7"}],"description":"Dev","businessName":"Amul Milk Center","businessId":"VD627523"}],"service":[{"_id":{"$oid":"60a34da258d8b50011859c4d"},"service":"Amul Milk Cow","businessId":{"$oid":"60a34c76d8b10300111325ea"}},{"_id":{"$oid":"60a34dc7d8b10300111325f7"},"service":"Amul Milk Buffalo","businessId":{"$oid":"60a34c76d8b10300111325ea"}},{"_id":{"$oid":"620ea45b9a94ea160049cfc5"},"service":"Amul Ice Cream","businessId":{"$oid":"60a34c76d8b10300111325ea"}}]}

db.service.aggregate([{"$match":{"service":{"$regex":"Amul Milk"}}},{"$lookup":{"from":"business","localField":"businessId","foreignField":"_id","as":"businessName"}},{"$project":{"_id":0,"service":1,"businessName":{"$first":"$businessName.businessName"}}}])