db={"adverb":[{"advId":"myid","advTitle":"myTitle","advDescription":"test description","fromUser":"userid","subCategoryId":"catid","advLabel":"1","cityId":"cityid","areaName":"areaName","chatState":true,"geoPosition":{"latitude":21.61980691353274,"longitude":51.519725019871956},"advImages":[],"timeStamp":1646670847761,"visibility":false}],"categories":[{"catId":"catId","catTitle":"catTitle","catSub":[{"subId":"catid","subTitle":"آپارتمان"},{"subId":"123","subTitle":"ویلایی"}]}]}

db.adverb.aggregate([{"$lookup":{"from":"categories","localField":"subCategoryId","foreignField":"catSub.subId","as":"docs"}}])