Myujth

I am relatively new to mongodb. I have a document like:

 "_id" : ObjectId("5bcf50938847292ecbadc3c1"),
 "obsrvblKy" : "ABCDEFGHIJ",
 "obsrvblKnd" : "PRICE",
 "pblshrNm" : "BT",
 "pblshrSrc" : "BT",
 "dstrbtr" : "BT",
 "crtdOn" : ISODate("2018-10-23T12:47:15.544Z"),
 "qut" : [
 
 "qlfr" : "BID",
 "vl" : 100,
 "mrkTmstmp" : ISODate("2018-10-23T12:47:05.524Z"),
 "mrkDt" : ISODate("2018-10-23T00:00:00Z")
 ,
 
 "qlfr" : "ASK",
 "vl" : 101,
 "mrkTmstmp" : ISODate("2018-10-23T12:47:05.524Z"),
 "mrkDt" : ISODate("2018-10-23T00:00:00Z")
 ,
 
 "qlfr" : "MID",
 "vl" : 100.50,
 "mrkTmstmp" : ISODate("2018-10-23T12:47:05.524Z"),
 "mrkDt" : ISODate("2018-10-23T00:00:00Z")
 
 ],
 "mrkCurrncy" : "USD",
 "sttlmntDt" : "2018-10-30" 

I want this document to be transformed to a more simpler version enabling it to be downloaded into a CSV format.

 "obsrvblKy" : "ABCDEFGHIJ",
 "obsrvblKnd" : "PRICE",
 "pblshrNm" : "BT",
 "pblshrSrc" : "BT",
 "dstrbtr" : "BT",
 "Bid": 100,
 "Bid-Timestamp": ISODate("2018-10-23T12:47:05.524Z"),
 "Ask": 101,
 "Ask-Timestamp": ISODate("2018-10-23T12:47:05.524Z"),
 "Mid": 100.50,
 "Mid-Timestamp": ISODate("2018-10-23T12:47:05.524Z")

Can someone point me to how this can be done.

You can use below aggregation

db.collection.aggregate([
 "$replaceRoot": 
 "newRoot": 
 "$mergeObjects": [
 "$$ROOT",
 "$arrayToObject": 
 "$reduce": 
 "input": "$qut",
 "initialValue": ,
 "in": 
 "$concatArrays": [
 [
 "k": "$$this.qlfr", "v": "$$this.vl" ,
 "k": "$concat": ["$$this.qlfr", "-", "TimeStamp"] , "v": "$$this.mrkTmstmp" 
 ],
 "$$value"
 ]
 
 
 
 ]
 
 ,
 "$project": "qut": 0 
])

Output

[
 
 "ASK": 101,
 "ASK-TimeStamp": ISODate("2018-10-23T12:47:05.524Z"),
 "BID": 100,
 "BID-TimeStamp": ISODate("2018-10-23T12:47:05.524Z"),
 "MID": 100.5,
 "MID-TimeStamp": ISODate("2018-10-23T12:47:05.524Z"),
 "_id": ObjectId("5bcf50938847292ecbadc3c1"),
 "crtdOn": ISODate("2018-10-23T12:47:15.544Z"),
 "dstrbtr": "BT",
 "mrkCurrncy": "USD",
 "obsrvblKnd": "PRICE",
 "obsrvblKy": "ABCDEFGHIJ",
 "pblshrNm": "BT",
 "pblshrSrc": "BT",
 "sttlmntDt": "2018-10-30"
 
]

You can below aggregation in 3.6 version.

db.colname.aggregate([
"$replaceRoot":
 "newRoot":
 "$reduce":
 "input":"$qut",
 "initialValue":"$$ROOT",
 "in":
 "$mergeObjects":[
 "$arrayToObject":[[
 ["$$this.qlfr","$$this.vl"],
 ["$concat":["$$this.qlfr","-","TimeStamp"],"$$this.mrkTmstmp"]
 ]],
 "$$value"
 ]
 
 
 
,
"$project":"crtdOn":0,"qut":0,"mrkCurrncy":0,"sttlmntDt":0
])