[{id:1,name:"sree",userId:"001",paymentData:{user_Id:"001",amount:200}},{id:1,name:"sree",userId:"001",paymentData:{user_Id:"002",amount:200}}]

db.collection.aggregate([{$addFields:{isEqual:{$eq:["$userId","$paymentData.user_Id"]}}},{$match:{isEqual:true}}])