[{_id:ObjectId("5ab9cbe531c2ab715d42129a"),p_id:ObjectId("507f191e810c19729de860ea"),name:"elmaro",mobile:112466,area:"texas",mapped:[{_id:ObjectId("5e13642ee88247a6b4f2c0f9"),p_id:ObjectId("507f191e810c19729de860eb"),effected:"12",tested:"14255",negative:"1658451"},{_id:ObjectId("5e13642ee88247a6b4f2c0f1"),p_id:ObjectId("507f191e810c19729de860ea"),effected:"254",tested:"54851",negative:"158521541"}]},{_id:ObjectId("5ab9cbe531c2ab715d52128a"),p_id:ObjectId("507f191e810c19729de860ea"),name:"hukke",mobile:112466,area:"texas",mapped:[{_id:ObjectId("5e13642ee88247a6b4f2c0f9"),p_id:ObjectId("507f191e810c19729de860ea"),effected:"1222",tested:"3545621",negative:"354168512"}]}]

db.collection.aggregate([{$addFields:{mapped:{$filter:{input:"$mapped",cond:{$eq:["$$this.p_id","$p_id"]}}}}}])