Mongo 3.6: Removing Duplicates - mongodb
Using the following command I get all the duplicate values in my collection based on the "no" field:
db.books.aggregate([{ $group: { _id: {no: "$no"}, uniqueIds: {$addToSet: "$_id"}, count: {$sum: 1}}}, { $match: { count: {"$gt": 1}}}, { $sort: {count: -1}}])
This returns the following:
{ "_id" : { "no" : 160541455 }, "uniqueIds" : [ ObjectId("5b3a3a3bd6194c5bfe40a523"), ObjectId("5b3a345dd6194c5bfe3deefa"), ObjectId("5b3a3509d6194c5bfe3e2e29"), ObjectId("5b3a3440d6194c5bfe3de3b4"), ObjectId("5b3a336ad6194c5bfe3d80a9"), ObjectId("5b3a3600d6194c5bfe3eb073"), ObjectId("5b3a37e1d6194c5bfe3f96f0"), ObjectId("5b3a35aed6194c5bfe3e8b83"), ObjectId("5b3a36ead6194c5bfe3f2dbd"), ObjectId("5b3a3ea6d6194c5bfe42d794"), ObjectId("5b3a3731d6194c5bfe3f50d2"), ObjectId("5b3a399bd6194c5bfe40676c") ], "count" : 12 }
{ "_id" : { "no" : 105900593 }, "uniqueIds" : [ ObjectId("5b3a3efad6194c5bfe42fc1f"), ObjectId("5b3a3df3d6194c5bfe429191"), ObjectId("5b3a3697d6194c5bfe3f0ca9"), ObjectId("5b3a385fd6194c5bfe3fdced"), ObjectId("5b3a3b69d6194c5bfe416901"), ObjectId("5b3a347ed6194c5bfe3dfeff"), ObjectId("5b3a335ad6194c5bfe3d7c15"), ObjectId("5b3a3887d6194c5bfe3feaad"), ObjectId("5b3a38b8d6194c5bfe400088"), ObjectId("5b3a358dd6194c5bfe3e81ea"), ObjectId("5b3a3b3fd6194c5bfe4157bc"), ObjectId("5b3a3decd6194c5bfe428efa") ], "count" : 12 }
{ "_id" : { "no" : 144919593 }, "uniqueIds" : [ ObjectId("5b3a3e46d6194c5bfe42b277"), ObjectId("5b3a3c22d6194c5bfe41b05a"), ObjectId("5b3a398cd6194c5bfe4065be"), ObjectId("5b3a37a1d6194c5bfe3f8239"), ObjectId("5b3a3678d6194c5bfe3f0496"), ObjectId("5b3a33d2d6194c5bfe3db42c"), ObjectId("5b3a36e6d6194c5bfe3f2d4d"), ObjectId("5b3a3d05d6194c5bfe421e97"), ObjectId("5b3a384ad6194c5bfe3fd621"), ObjectId("5b3a3565d6194c5bfe3e6c44") ], "count" : 10 }
{ "_id" : { "no" : 86204442 }, "uniqueIds" : [ ObjectId("5b3a3df5d6194c5bfe429204"), ObjectId("5b3a3d1cd6194c5bfe4224a1"), ObjectId("5b3a3b33d6194c5bfe415288"), ObjectId("5b3a3934d6194c5bfe403ed9"), ObjectId("5b3a3c39d6194c5bfe41b664"), ObjectId("5b3a37dbd6194c5bfe3f961c"), ObjectId("5b3a3688d6194c5bfe3f0613"), ObjectId("5b3a3731d6194c5bfe3f50c6"), ObjectId("5b3a37dfd6194c5bfe3f9697") ], "count" : 9 }
{ "_id" : { "no" : 119417424 }, "uniqueIds" : [ ObjectId("5b3a3b34d6194c5bfe4152a5"), ObjectId("5b3a392cd6194c5bfe403b21"), ObjectId("5b3a399ad6194c5bfe406736"), ObjectId("5b3a38b9d6194c5bfe4000c7"), ObjectId("5b3a3ea5d6194c5bfe42d77f"), ObjectId("5b3a374cd6194c5bfe3f5c9f"), ObjectId("5b3a33d9d6194c5bfe3db4e3"), ObjectId("5b3a3386d6194c5bfe3d8ab8"), ObjectId("5b3a3857d6194c5bfe3fd754") ], "count" : 9 }
{ "_id" : { "no" : 159374794 }, "uniqueIds" : [ ObjectId("5b3a3e52d6194c5bfe42b3b8"), ObjectId("5b3a3c0fd6194c5bfe41ac10"), ObjectId("5b3a38f5d6194c5bfe401b2f"), ObjectId("5b3a37afd6194c5bfe3f83b7"), ObjectId("5b3a33ebd6194c5bfe3dbc27"), ObjectId("5b3a36edd6194c5bfe3f2e78"), ObjectId("5b3a34ced6194c5bfe3e1b24"), ObjectId("5b3a3b36d6194c5bfe41530d"), ObjectId("5b3a3753d6194c5bfe3f5f99") ], "count" : 9 }
{ "_id" : { "no" : 159363089 }, "uniqueIds" : [ ObjectId("5b3a3e4fd6194c5bfe42b340"), ObjectId("5b3a3e0ad6194c5bfe429a1f"), ObjectId("5b3a3854d6194c5bfe3fd708"), ObjectId("5b3a34cbd6194c5bfe3e1acb"), ObjectId("5b3a38f4d6194c5bfe401afb"), ObjectId("5b3a36c4d6194c5bfe3f20aa"), ObjectId("5b3a3a06d6194c5bfe409119"), ObjectId("5b3a36ecd6194c5bfe3f2e2b"), ObjectId("5b3a3764d6194c5bfe3f6439") ], "count" : 9 }
{ "_id" : { "no" : 101412948 }, "uniqueIds" : [ ObjectId("5b3a3ea0d6194c5bfe42d708"), ObjectId("5b3a37b7d6194c5bfe3f8749"), ObjectId("5b3a3712d6194c5bfe3f4510"), ObjectId("5b3a334ed6194c5bfe3d759b"), ObjectId("5b3a3929d6194c5bfe403aca"), ObjectId("5b3a36f3d6194c5bfe3f334d"), ObjectId("5b3a39bad6194c5bfe407541"), ObjectId("5b3a3477d6194c5bfe3df66b"), ObjectId("5b3a35bdd6194c5bfe3e9233") ], "count" : 9 }
{ "_id" : { "no" : 107412155 }, "uniqueIds" : [ ObjectId("5b3a3e52d6194c5bfe42b3d1"), ObjectId("5b3a3a3bd6194c5bfe40a53a"), ObjectId("5b3a399cd6194c5bfe40678d"), ObjectId("5b3a390fd6194c5bfe402698"), ObjectId("5b3a3c0fd6194c5bfe41ac28"), ObjectId("5b3a346ad6194c5bfe3df338"), ObjectId("5b3a3584d6194c5bfe3e718a"), ObjectId("5b3a373cd6194c5bfe3f5563"), ObjectId("5b3a37e5d6194c5bfe3f97d6") ], "count" : 9 }
{ "_id" : { "no" : 156426829 }, "uniqueIds" : [ ObjectId("5b3a3cc6d6194c5bfe421829"), ObjectId("5b3a3f01d6194c5bfe430069"), ObjectId("5b3a3a29d6194c5bfe40a378"), ObjectId("5b3a37c9d6194c5bfe3f8fdc"), ObjectId("5b3a3558d6194c5bfe3e6b19"), ObjectId("5b3a3dabd6194c5bfe428666"), ObjectId("5b3a366ad6194c5bfe3f0356"), ObjectId("5b3a36e3d6194c5bfe3f2d02"), ObjectId("5b3a3798d6194c5bfe3f8160") ], "count" : 9 }
{ "_id" : { "no" : 104966976 }, "uniqueIds" : [ ObjectId("5b3a3c35d6194c5bfe41b614"), ObjectId("5b3a3a04d6194c5bfe4090e9"), ObjectId("5b3a3d19d6194c5bfe422451"), ObjectId("5b3a37a7d6194c5bfe3f82bc"), ObjectId("5b3a348cd6194c5bfe3e034c"), ObjectId("5b3a3e58d6194c5bfe42b5d2"), ObjectId("5b3a345cd6194c5bfe3deee2"), ObjectId("5b3a35aad6194c5bfe3e8b15"), ObjectId("5b3a36c3d6194c5bfe3f208b") ], "count" : 9 }
{ "_id" : { "no" : 105460396 }, "uniqueIds" : [ ObjectId("5b3a3e04d6194c5bfe429777"), ObjectId("5b3a3b99d6194c5bfe417eb6"), ObjectId("5b3a38c7d6194c5bfe400533"), ObjectId("5b3a3e6ed6194c5bfe42bbc6"), ObjectId("5b3a38f5d6194c5bfe401b1d"), ObjectId("5b3a3ee8d6194c5bfe42f43f"), ObjectId("5b3a39a5d6194c5bfe4069ec"), ObjectId("5b3a3a07d6194c5bfe409134") ], "count" : 8 }
{ "_id" : { "no" : 158805980 }, "uniqueIds" : [ ObjectId("5b3a3efad6194c5bfe42fc7c"), ObjectId("5b3a3abed6194c5bfe41470a"), ObjectId("5b3a337cd6194c5bfe3d89c3"), ObjectId("5b3a33bdd6194c5bfe3db218"), ObjectId("5b3a3dfcd6194c5bfe42955f"), ObjectId("5b3a3be7d6194c5bfe41a820"), ObjectId("5b3a3444d6194c5bfe3de564"), ObjectId("5b3a391fd6194c5bfe4039d5") ], "count" : 8 }
{ "_id" : { "no" : 107411546 }, "uniqueIds" : [ ObjectId("5b3a3c0fd6194c5bfe41ac2a"), ObjectId("5b3a3b37d6194c5bfe415337"), ObjectId("5b3a390fd6194c5bfe402699"), ObjectId("5b3a399cd6194c5bfe406793"), ObjectId("5b3a373cd6194c5bfe3f5565"), ObjectId("5b3a346ad6194c5bfe3df339"), ObjectId("5b3a3584d6194c5bfe3e718b"), ObjectId("5b3a37e5d6194c5bfe3f97d7") ], "count" : 8 }
{ "_id" : { "no" : 128015326 }, "uniqueIds" : [ ObjectId("5b3a3ed1d6194c5bfe42f1a3"), ObjectId("5b3a3df4d6194c5bfe4291f9"), ObjectId("5b3a38bed6194c5bfe400437"), ObjectId("5b3a381dd6194c5bfe3fd124"), ObjectId("5b3a3465d6194c5bfe3df1a7"), ObjectId("5b3a36cdd6194c5bfe3f2569"), ObjectId("5b3a3719d6194c5bfe3f4637"), ObjectId("5b3a377bd6194c5bfe3f7dfa") ], "count" : 8 }
{ "_id" : { "no" : 123932233 }, "uniqueIds" : [ ObjectId("5b3a3df3d6194c5bfe429177"), ObjectId("5b3a3d1dd6194c5bfe4224be"), ObjectId("5b3a3c39d6194c5bfe41b681"), ObjectId("5b3a3c0fd6194c5bfe41ac0d"), ObjectId("5b3a34e2d6194c5bfe3e22e6"), ObjectId("5b3a349fd6194c5bfe3e077d"), ObjectId("5b3a35aed6194c5bfe3e8b86"), ObjectId("5b3a3886d6194c5bfe3fea0f") ], "count" : 8 }
{ "_id" : { "no" : 150567857 }, "uniqueIds" : [ ObjectId("5b3a3a97d6194c5bfe413812"), ObjectId("5b3a39d9d6194c5bfe408888"), ObjectId("5b3a3816d6194c5bfe3fcd1b"), ObjectId("5b3a3635d6194c5bfe3ef80f"), ObjectId("5b3a3480d6194c5bfe3e011d"), ObjectId("5b3a34ead6194c5bfe3e2661"), ObjectId("5b3a33f8d6194c5bfe3dc477"), ObjectId("5b3a3529d6194c5bfe3e616a") ], "count" : 8 }
{ "_id" : { "no" : 143815726 }, "uniqueIds" : [ ObjectId("5b3a3b46d6194c5bfe415985"), ObjectId("5b3a3a08d6194c5bfe409172"), ObjectId("5b3a39a5d6194c5bfe4069fd"), ObjectId("5b3a33dad6194c5bfe3db527"), ObjectId("5b3a399cd6194c5bfe4067e7"), ObjectId("5b3a348fd6194c5bfe3e03a3"), ObjectId("5b3a37bcd6194c5bfe3f89c6"), ObjectId("5b3a36b7d6194c5bfe3f1cb9") ], "count" : 8 }
{ "_id" : { "no" : 143839331 }, "uniqueIds" : [ ObjectId("5b3a3ee8d6194c5bfe42f43a"), ObjectId("5b3a3e6ed6194c5bfe42bbbd"), ObjectId("5b3a3e04d6194c5bfe429773"), ObjectId("5b3a38c7d6194c5bfe40052f"), ObjectId("5b3a3a07d6194c5bfe40912e"), ObjectId("5b3a38f5d6194c5bfe401b19"), ObjectId("5b3a3b99d6194c5bfe417eb0"), ObjectId("5b3a39a5d6194c5bfe4069e8") ], "count" : 8 }
{ "_id" : { "no" : 99764925 }, "uniqueIds" : [ ObjectId("5b3a39f7d6194c5bfe408db1"), ObjectId("5b3a39c0d6194c5bfe4075eb"), ObjectId("5b3a399cd6194c5bfe40678a"), ObjectId("5b3a37bcd6194c5bfe3f89bf"), ObjectId("5b3a368ad6194c5bfe3f0673"), ObjectId("5b3a348fd6194c5bfe3e0391"), ObjectId("5b3a3578d6194c5bfe3e6e39"), ObjectId("5b3a36b7d6194c5bfe3f1ca8") ], "count" : 8 }
Question: What is the easiest and quickest way to remove the duplicates in Mongo 3.6.5? How must I edit the above command to achieve this?
I have tried the following but it doesn't work:
db.books.aggregate([ { $group:{ _id: {no: "$no" }, uniqueIds: { $addToSet: "$_id" }, count: {$sum: 1} } }, { $match: {count: {$gt: 1} } } ]).forEach(function(doc){ doc.uniqueIds.shift(); db.uniqueIds.remove({_id : {$in: doc.uniqueIds}});})
Mongo-3.6: Here ReviewId is my Unique Key, want to Delete my duplicate reviewId value
cursor=db.reviewsAnalysed.aggregate([{"$group": {"_id": {"reviewId":"$reviewId"},
"unique_ids": {"$addToSet": "$_id"}, "count": {"$sum": 1 } } }])
response = []
for doc in cursor:
del doc["unique_ids"][0]
for id in doc["unique_ids"]:
response.append(id)
db.reviewsAnalysed.remove({"_id": {"$in": response}})
Related
MongoDB Query that will $project document values in horizontal format
Im trying to create a query that will project or show the field in HORIZONTAL format. Below is my sample collection and the expected output. BTW, Im also using jaspersoft studio to create the report but i think my output should be done in mongodb query. Hope someone can help. Thanks!
"_id" : ObjectId("60ddc6f44c893c117141e9b9"),
"observationvalues" : [
{
"_id" : ObjectId("60ddc6f44c893c117141e9c3"),
"name" : "Systolic BP",
"resultvalue" : "88.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9c2"),
"name" : "Diastolic BP",
"resultvalue" : "66.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9c1"),
"name" : "Weight",
"resultvalue" : "90.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9c5"),
"name" : "Height",
"resultvalue" : null
}
],
"createdat" : ISODate("2021-07-01T13:45:24.679Z"),
"modifiedat" : ISODate("2021-07-01T13:45:24.679Z"),
"statusflag" : "A"
"_id" : ObjectId("60ddc6f44c893c117141e8b8"),
"observationvalues" : [
{
"_id" : ObjectId("60ddc6f44c893c117141e9b3"),
"name" : "Systolic BP",
"resultvalue" : "84.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9b2"),
"name" : "Diastolic BP",
"resultvalue" : "63.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9b1"),
"name" : "Weight",
"resultvalue" : "99.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9b5"),
"name" : "Height",
"resultvalue" : 172.00
}
],
"createdat" : ISODate("2021-07-02T13:45:24.679Z"),
"modifiedat" : ISODate("2021-07-02T13:45:24.679Z"),
"statusflag" : "A"
"_id" : ObjectId("60ddc6f44c893c117141e7b7"),
"observationvalues" : [
{
"_id" : ObjectId("60ddc6f44c893c117141e9a3"),
"name" : "Systolic BP",
"resultvalue" : "81.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9a2"),
"name" : "Diastolic BP",
"resultvalue" : "65.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9a1"),
"name" : "Weight",
"resultvalue" : "96.00"
},
{
"_id" : ObjectId("60ddc6f44c893c117141e9a5"),
"name" : "Height",
"resultvalue" : 165.00
}
],
"createdat" : ISODate("2021-07-03T13:45:24.679Z"),
"modifiedat" : ISODate("2021-07-03T13:45:24.679Z"),
"statusflag" : "A",
The expected Output will be:
{"createdat" : "2021-07-01T13:45:24.679Z", "Systolic BP" : 88.00 ,"Diastolic BP" : 66.00 ,"Weight": 90.00 ,"Height":null }
{"createdat" : "2021-07-01T13:45:24.679Z", "Systolic BP" : 84.00 ,"Diastolic BP" : 63.00 ,"Weight": 99.00 ,"Height":172.00 }
{"createdat" : "2021-07-03T13:45:24.679Z", "Systolic BP" : 81.00 ,"Diastolic BP" : 65.00 ,"Weight": 96.00 ,"Height":165.00 }
I have created my query but it is not having the output in one line grouped for each createdat field
{
$project : {
_id: {
"systolic": {"$cond": [ { "$eq": ["$name","Systolic BP" ] }, "$resultvalue","" ] },
"diastolic": {"$cond": [ { "$eq": ["$name","Diastolic BP" ] }, "$resultvalue","" ] },
"weight": {"$cond": [ { "$eq": ["$name","Weight" ] }, "$resultvalue","" ] },
"height": {"$cond": [ { "$eq": ["$name","Height" ] }, "$resultvalue","" ] },
"create": "$createdat"
}
}
},
Your expected data output could be done like this: playground
[
{
"$project": {
"createdat": 1,
"rows": {
"$arrayToObject": {
"$map": {
"input": "$observationvalues",
"in": {
"k": "$$this.name",
"v": {
"$convert": {
"input": "$$this.resultvalue",
"to": "double",
"onError": null,
"onNull": null
}
}
}
}
}
}
}
},
{
"$addFields": {
"rows.create": "$createdat"
}
},
{
"$replaceRoot": {
"newRoot": "$rows"
}
},
{
"$match": {
"Systolic BP": 84.00
}
}
]
To get them in one line you should look for some JSON formater.
Get all possible combinations from array in MongoDB aggregation 🚀
How to do aggregation ($group) by the same values ​​from the array? Not all at once, but few or all, if any. I can do $group by one word, but I also need all possible variations...
Collection example:
{"keywords": ["gta", "distribution", "keys"]}
{"keywords": ["gta", "online", "moto", "races"]}
{"keywords": ["gta", "online", "samp"]}
Result example:
"gta" - 3 matches
"online" - 2 matches
"gta online" - 2 matches
You could use $reduce to extract all combinations of pairs from an array. I've started from this post and I've added the current item, $unwind the
initial array and count the items :
db.test.aggregate([
{
$project: {
pairs: {
$reduce: {
input: { $range: [0, { $size: "$keywords" }] },
initialValue: [],
in: {
$concatArrays: [
"$$value",
[[{ $arrayElemAt: ["$keywords", "$$this"] }]],
{
$let: {
vars: { i: "$$this" },
in: {
$map: {
input: { $range: [{ $add: [1, "$$i"] }, { $size: "$keywords" }] },
in: [{ $arrayElemAt: ["$keywords", "$$i"] }, { $arrayElemAt: ["$keywords", "$$this"] }]
}
}
}
}
]
}
}
}
}
}, {
$unwind: "$pairs"
}, {
$group: {
_id: "$pairs",
count: { $sum: 1 }
}
}
])
Output :
{ "_id" : [ "online", "samp" ], "count" : 1 }
{ "_id" : [ "gta", "samp" ], "count" : 1 }
{ "_id" : [ "online", "races" ], "count" : 1 }
{ "_id" : [ "moto", "races" ], "count" : 1 }
{ "_id" : [ "gta", "keys" ], "count" : 1 }
{ "_id" : [ "races" ], "count" : 1 }
{ "_id" : [ "gta", "distribution" ], "count" : 1 }
{ "_id" : [ "samp" ], "count" : 1 }
{ "_id" : [ "distribution", "keys" ], "count" : 1 }
{ "_id" : [ "gta" ], "count" : 3 }
{ "_id" : [ "online" ], "count" : 2 }
{ "_id" : [ "keys" ], "count" : 1 }
{ "_id" : [ "gta", "online" ], "count" : 2 }
{ "_id" : [ "moto" ], "count" : 1 }
{ "_id" : [ "online", "moto" ], "count" : 1 }
{ "_id" : [ "distribution" ], "count" : 1 }
{ "_id" : [ "gta", "moto" ], "count" : 1 }
{ "_id" : [ "gta", "races" ], "count" : 1 }
If you need more combinations, you may need to update the $reduce stage above
How to write mongo query
How I can get the total number of seats available for a particular movie (seats present in all the theatres for that movie) from the mongodb schema below.
I need to write a mongo query to get the results
{
"_id" : ObjectId("5d637b5ce27c7d60e5c42ae7"),
"name" : "Bangalore",
"movies" : [
{
"name" : "KGF",
"theatres" : [
{
"name" : "PVR",
"seats" : 45
},
{
"name" : "IMAX",
"seats" : 46
}
]
},
{
"name" : "Avengers",
"theatres" : [
{
"name" : "IMAX",
"seats" : 50
}
]
}
],
"_class" : "com.BMS_mongo.ZZ_BMS_mongo_demo.Entity.CityInfo"
}
I have written this code :
db.cities.aggregate( [
{ "$unwind" : "$movies" }, { "$unwind" : "$theatres" } ,
{ "$group" : { _id : "$movies.theatre`enter code here`s.seats" ,
total : { "$sum" : "$seats" } }
}
] )
My schema:
The following query can get us the expected output:
db.collection.aggregate([
{
$unwind:"$movies"
},
{
$unwind:"$movies.theatres"
},
{
$group:{
"_id":"$movies.name",
"movie":{
$first:"$movies.name"
},
"totalSeats":{
$sum:"$movies.theatres.seats"
}
}
},
{
$project:{
"_id":0
}
}
]).pretty()
Data set:
{
"_id" : ObjectId("5d637b5ce27c7d60e5c42ae7"),
"name" : "Bangalore",
"movies" : [
{
"name" : "KGF",
"theatres" : [
{
"name" : "PVR",
"seats" : 45
},
{
"name" : "IMAX",
"seats" : 46
}
]
},
{
"name" : "Avengers",
"theatres" : [
{
"name" : "IMAX",
"seats" : 50
}
]
}
],
"_class" : "com.BMS_mongo.ZZ_BMS_mongo_demo.Entity.CityInfo"
}
Output:
{ "movie" : "Avengers", "totalSeats" : 50 }
{ "movie" : "KGF", "totalSeats" : 91 }
Query:
db.movie.aggregate([{ $unwind: { path: "$movies",} },
{ $unwind: { path: "$movies.theatres",} },
{ $group: { _id: "$movies.name", "moviename": { $first: "$movies.name" },
"totalSeats": { $sum: "$movies.theatres.seats" }} }])
I got the answer using this query ...
db.cities.aggregate( [
{ "$match" : { "name" : "Bangalore" } },
{ "$unwind" : "$movies" } ,
{ "$match" : {"movies.name" : "KGF"} },
{ "$unwind" : "$theatres" },
{ "$group" : { _id : "$movies.name", total : { "$sum" : "$movies.theatres.seats"
} } }
] )
mongodb aggregation $group and then $push a object
this is my data :
> db.bookmarks.find({"userId" : "56b9b74bf976ab70ff6b9999"}).pretty()
{
"_id" : ObjectId("56c2210fee4a33579f4202dd"),
"userId" : "56b9b74bf976ab70ff6b9999",
"items" : [
{
"itemId" : "28",
"timestamp" : "2016-02-12T18:07:28Z"
},
{
"itemId" : "29",
"timestamp" : "2016-02-12T18:07:29Z"
},
{
"itemId" : "30",
"timestamp" : "2016-02-12T18:07:30Z"
},
{
"itemId" : "31",
"timestamp" : "2016-02-12T18:07:31Z"
},
{
"itemId" : "32",
"timestamp" : "2016-02-12T18:07:32Z"
},
{
"itemId" : "33",
"timestamp" : "2016-02-12T18:07:33Z"
},
{
"itemId" : "34",
"timestamp" : "2016-02-12T18:07:34Z"
}
]
}
I want to have something like (actually i hope the _id can become userId too) :
{
"_id" : "56b9b74bf976ab70ff6b9999",
"items" : [
{ "itemId": "32", "timestamp": "2016-02-12T18:07:32Z" },
{ "itemId": "31", "timestamp": "2016-02-12T18:07:31Z" },
{ "itemId": "30", "timestamp": "2016-02-12T18:07:30Z" }
]
}
What I have now :
> db.bookmarks.aggregate(
... { $match: { "userId" : "56b9b74bf976ab70ff6b9999" } },
... { $unwind: '$items' },
... { $sort: { 'items.timestamp': -1} },
... { $skip: 2 },
... { $limit: 3},
... { $group: { '_id': '$userId' , items: { $push: '$items.itemId' } } }
... ).pretty()
{ "_id" : "56b9b74bf976ab70ff6b9999", "items" : [ "32", "31", "30" ] }
i tried to read the document in mongo and find out i can $push, but somehow i cannot find a way to push such object, which is not defined anywhere in the whole object. I want to have the timestamp also.. but i don't know how should i modified the $group (or others??) to do so. thanks for helping!
This code, which I tested in the MongoDB 3.2.1 shell, should give you the output format that you want:
> db.bookmarks.aggregate(
{ "$match" : { "userId" : "Ursula" } },
{ "$unwind" : "$items" },
{ "$sort" : { "items.timestamp" : -1 } },
{ "$skip" : 2 },
{ "$limit" : 3 },
{ "$group" : { "_id" : "$userId", items: { "$push" : { "myPlace" : "$items.itemId", "myStamp" : "$items.timestamp" } } } } ).pretty()
Running the above will produce this output:
{
"_id" : "Ursula",
"items" : [
{
"myPlace" : "52",
"myStamp" : ISODate("2016-02-13T18:07:32Z")
},
{
"myPlace" : "51",
"myStamp" : ISODate("2016-02-13T18:07:31Z")
},
{
"myPlace" : "50",
"myStamp" : ISODate("2016-02-13T18:07:30Z")
}
]
}
In MongoDB version 3.2.x, you can also use the $out operator in the very last stage of the aggregation pipeline, and have the output of the aggregation query written to a collection. Here is the code I used:
> db.bookmarks.aggregate(
{ "$match" : { "userId" : "Ursula" } },
{ "$unwind" : "$items" },
{ "$sort" : { "items.timestamp" : -1 } },
{ "$skip" : 2 },
{ "$limit" : 3 },
{ "$group" : { "_id" : "$userId", items: { "$push" : { "myPlace" : "$items.itemId", "myStamp" : "$items.timestamp" } } } },
{ "$out" : "ursula" } )
This gives me a collection named "ursula":
> show collections
ursula
and I can query that collection:
> db.ursula.find().pretty()
{
"_id" : "Ursula",
"items" : [
{
"myPlace" : "52",
"myStamp" : ISODate("2016-02-13T18:07:32Z")
},
{
"myPlace" : "51",
"myStamp" : ISODate("2016-02-13T18:07:31Z")
},
{
"myPlace" : "50",
"myStamp" : ISODate("2016-02-13T18:07:30Z")
}
]
}
>
Last of all, this is the input document I used in the aggregation query. You can compare this document to how I coded the aggregation query to see how I built the new items array.
> db.bookmarks.find( { "userId" : "Ursula" } ).pretty()
{
"_id" : ObjectId("56c240ed55f2f6004dc3b25c"),
"userId" : "Ursula",
"items" : [
{
"itemId" : "48",
"timestamp" : ISODate("2016-02-13T18:07:28Z")
},
{
"itemId" : "49",
"timestamp" : ISODate("2016-02-13T18:07:29Z")
},
{
"itemId" : "50",
"timestamp" : ISODate("2016-02-13T18:07:30Z")
},
{
"itemId" : "51",
"timestamp" : ISODate("2016-02-13T18:07:31Z")
},
{
"itemId" : "52",
"timestamp" : ISODate("2016-02-13T18:07:32Z")
},
{
"itemId" : "53",
"timestamp" : ISODate("2016-02-13T18:07:33Z")
},
{
"itemId" : "54",
"timestamp" : ISODate("2016-02-13T18:07:34Z")
}
]
}
Use field value as key
I am doing this query
db.analytics.aggregate([
{
$match: {"event":"USER_SENTIMENT"}
},
{ $group: {
_id: {brand:"$data.brandId",sentiment:"$data.sentiment"},
count: {$sum : 1}
}
},
{ $group: {
_id: "$_id.brand",
sentiments: {$addToSet : {sentiment:"$_id.sentiment", count:"$count"}}
}
}
])
Which generates that :
{
"result" : [
{
"_id" : 57,
"sentiments" : [
{
"sentiment" : "Meh",
"count" : 4
}
]
},
{
"_id" : 376,
"sentiments" : [
{
"sentiment" : "Meh",
"count" : 1
},
{
"sentiment" : "Happy",
"count" : 1
},
{
"sentiment" : "Confused",
"count" : 1
}
]
}
],
"ok" : 1
}
But What I want is that :
[
{
"_id" : 57,
"Meh" : 4
},
{
"_id" : 376,
"Meh" : 1,
"Happy" : 1,
"Confused" : 1
}
]
Any idea on how to transform that? The blocking point for me is to transform a value into a key.