Database
[{"_id":ObjectId("62b2beb8bfe272962f274942"),"CDF":{"UTILITYTYPE":{"D1":{"G1":"12387835","G2":"02-06-2022 13:03:23","G22":{"NAME":"LARSEN AND TOUBRO LIMITED"}},"D5":{"EVENT":[{"CODE":"14","TIME":"23-05-2022 09:23:39","STATUS":"0","SNAPSHOT":[{"PARAMCODE":"P1-2-1-1-0","VALUE":"218.39","UNIT":"V"},{"PARAMCODE":"P1-2-2-1-0","VALUE":"243.67","UNIT":"V"},{"PARAMCODE":"P1-2-3-1-0","VALUE":"241.37","UNIT":"V"},{"PARAMCODE":"P2-1-1-1-0","VALUE":"0.456","UNIT":"A"},{"PARAMCODE":"P2-1-2-1-0","VALUE":"0","UNIT":"A"},{"PARAMCODE":"P2-1-3-1-0","VALUE":"0","UNIT":"A"},{"PARAMCODE":"P4-1-1-0-0","VALUE":"-0.99","UNIT":"NA"},{"PARAMCODE":"P4-2-1-0-0","VALUE":"0","UNIT":"NA"},{"PARAMCODE":"P4-3-1-0-0","VALUE":"0","UNIT":"NA"},{"PARAMCODE":"P7-1-5-2-0","VALUE":"2383.03","UNIT":"k"}]},{"CODE":"14","TIME":"23-05-2022 10:40:49","STATUS":"1","SNAPSHOT":[{"PARAMCODE":"P1-2-1-1-0","VALUE":"227.58","UNIT":"V"},{"PARAMCODE":"P1-2-2-1-0","VALUE":"236.78","UNIT":"V"},{"PARAMCODE":"P1-2-3-1-0","VALUE":"236.78","UNIT":"V"},{"PARAMCODE":"P2-1-1-1-0","VALUE":"0","UNIT":"A"},{"PARAMCODE":"P2-1-2-1-0","VALUE":"0","UNIT":"A"},{"PARAMCODE":"P2-1-3-1-0","VALUE":"0","UNIT":"A"},{"PARAMCODE":"P4-1-1-0-0","VALUE":"0","UNIT":"NA"},{"PARAMCODE":"P4-2-1-0-0","VALUE":"0","UNIT":"NA"},{"PARAMCODE":"P4-3-1-0-0","VALUE":"0","UNIT":"NA"},{"PARAMCODE":"P7-1-5-2-0","VALUE":"2383.16","UNIT":"k"}]}]}}}}]
Query
db.collection.aggregate([{$set:{"CDF.UTILITYTYPE.D5.EVENT":{$map:{input:"$CDF.UTILITYTYPE.D5.EVENT",as:"event",in:{"$mergeObjects":["$$event",{SNAPSHOT:{$filter:{input:"$$event.SNAPSHOT",as:"d",cond:{$eq:["$$d.UNIT","V"]}}}}]}}}}}])