temporaryshifts is equal to
[{_id:123,
arr:[{_id:123321,name:"Bluh Bluh",date:"bluh bluh"}]
}]
so i want to access temporaryshifts[0].arr[0]
but i dont know how to access
$project:{
shiftArr:{$arrayElemAt:['$temporaryshifts',0]}
}
You have to make use of the let operators to make use of two $arrayElemAt Operators.
db.collection.aggregate([
{
"$project": {
"temporaryshifts": {
"$let": {
"vars": {
"masterKey": {
"$arrayElemAt": [
"$temporaryshifts",
0
]
}
},
"in": {
"$arrayElemAt": [
"$$masterKey.arr",
0
]
}
},
}
},
},
])
Mongo Playground Sample Execution
To Understand Properly i Am taking this example and suppose that this our data
`
[
{
_id: 123,
arr: [
{
_id: 123321,
name: "Bluh Bluh",
date: "bluh bluh"
},
{
_id: 1233219,
name: "Bluh Bluh2",
date: "bluh bluh2"
}
]
},
{
_id: 1234,
arr: [
{
_id: 1233214,
name: "Bluh Bluh4",
date: "bluh bluh4"
}
]
},
]
`
Can get temporaryshifts[0].arr[0] with this query
db.collection.aggregate([
{
"$match": {
"_id": 123
}
},
{
"$project": {
shiftArr: {
$arrayElemAt: [
"$arr",
0
]
}
}
}
])
You need to match at the first time to get the document and rest of thing arrayElementAt can manage.
Related
I'm working on simple program that counts total number of special units through n number of players.
I have documents similar to this (simplified), where array rosterUnits could be of length 0 to 7. There is a total of 7 special units. I need to know how many of each unit players have in roster.
{
{
_id: ObjectId(...),
member: {
rosterUnits: [ "Unit1", "Unit2", "Unit3", "Unit4"]
}
},
{
_id: ObjectId(...),
member: {
rosterUnits: [ "Unit1", "Unit3"]
}
},
...
}
Expected result would be something like this:
{
_id: ...
result: [
{
name: "Unit1"
count: 2
},
{
name: "Unit2"
count: 1
},
{
name: "Unit3"
count: 2
},
...
{
name: "Unit7"
count: 0
}
]
}
How do I achieve this using aggregate pipeline?
EDIT (2/7/2023)
Excuse me everyone, I thought I provided enough details here but...
Documents are very big and pipeline until this stage is very long.
I wanted to spare you the trouble with the documents
I have guild with up to 50 players. I search for guild then $unwind members of guild and $lookup into members to get member.rosterUnit(s).
This is a full query I came up with:
db.getCollection('guilds').aggregate([
{ $match: { 'profile.id': 'jrl9Q-_CRDGdMyNjTQH1rQ' } },
//{ $match: { 'profile.id': { $in : ['jrl9Q-_CRDGdMyNjTQH1rQ', 'Tv_j9nhRTgufvH7C7oUYAA']} } },
{ $project: { member: 1, profile: 1 } },
{ $unwind: "$member" },
{
$lookup: {
from: "players",
localField: "member.playerId",
foreignField: "playerId",
pipeline: [
{
$project: {
profileStat: 1,
rosterUnit: {
$let: {
vars: { gls: ["JABBATHEHUTT:SEVEN_STAR", "JEDIMASTERKENOBI:SEVEN_STAR", "GRANDMASTERLUKE:SEVEN_STAR", "LORDVADER:SEVEN_STAR", "GLREY:SEVEN_STAR", "SITHPALPATINE:SEVEN_STAR", "SUPREMELEADERKYLOREN:SEVEN_STAR"], },
in: {
$reduce: {
input: "$rosterUnit",
initialValue: [],
in: {
$cond: {
if: { $gt: [{ $indexOfArray: ["$$gls", "$$this.definitionId"] }, -1] },
then: { $concatArrays: ["$$value", [{ definitionId: "$$this.definitionId", count: 1 }]] },
else: { $concatArrays: ["$$value", []] }
}
},
}
}
}
}
}
}
],
as: "member"
}
},
{
$addFields: {
member: { $arrayElemAt: ["$member", 0] },
gpStats: {
$let: {
vars: { member: { $arrayElemAt: ["$member", 0] } },
in: {
$reduce: {
input: "$$member.profileStat",
initialValue: {},
in: {
characterGp: {
$arrayElemAt: [
"$$member.profileStat.value",
{
$indexOfArray: [
"$$member.profileStat.nameKey",
"STAT_CHARACTER_GALACTIC_POWER_ACQUIRED_NAME"
]
}
]
},
shipGp: {
$arrayElemAt: [
"$$member.profileStat.value",
{
$indexOfArray: [
"$$member.profileStat.nameKey",
"STAT_SHIP_GALACTIC_POWER_ACQUIRED_NAME"
]
}
]
}
}
}
}
}
}
}
},
{
$group: {
_id: "$profile.id",
guildName: { $first: "$profile.name" },
memberCount: { $first: "$profile.memberCount" },
guildGp: { $first: "$profile.guildGalacticPower" },
totalGp: { $sum: { $sum: [{ $toInt: "$gpStats.characterGp" }, { $toInt: "$gpStats.shipGp" }] } },
avgTotalGp: { $avg: { $sum: [{ $toInt: "$gpStats.characterGp" }, { $toInt: "$gpStats.shipGp" }] } },
characterGp: { $sum: { $toInt: "$gpStats.characterGp" } },
shipGp: { $sum: { $toInt: "$gpStats.shipGp" } },
}
}
])
I want to add new field in group with desired result from above.
If I do $unwind on member.rosterUnit how do I go back to member grouping?
(Excuse me once again, this is my first question)
Use $unwind to deconstruct the rosterUnits array into separate documents.
Then use $group to group the documents by the rosterUnits values and calculate the count for each unit.
Then use $project to format the output to include only the name and count fields.
db.collection.aggregate([
{
$unwind: "$member.rosterUnits"
},
{
$group: {
_id: "$member.rosterUnits",
count: { $sum: 1 }
}
},
{
$project: {
_id: 0,
name: "$_id",
count: "$count"
}
}
])
Yes I think that the best way of do that is using aggregations.
I'm sure there is a better way to do it.
But here is the solution, I hope it works for you friend.
Basically we are going to use a "$group" aggregation and within it using an operator "$cond" and "$in" we are going to validate case by case if the searched element is found. In the case that it is so, we will add one and if the element is not found, zero.
I recommend you download mongodb compass to try it
Aggregation:
[{
$group: {
_id: null,
Unit1: {
$sum: {
$cond: [
{
$in: [
'Unit1',
'$member.rosterUnits'
]
},
1,
0
]
}
},
Unit2: {
$sum: {
$cond: [
{
$in: [
'Unit2',
'$member.rosterUnits'
]
},
1,
0
]
}
},
Unit3: {
$sum: {
$cond: [
{
$in: [
'Unit3',
'$member.rosterUnits'
]
},
1,
0
]
}
},
Unit4: {
$sum: {
$cond: [
{
$in: [
'Unit4',
'$member.rosterUnits'
]
},
1,
0
]
}
},
Unit5: {
$sum: {
$cond: [
{
$in: [
'Unit5',
'$member.rosterUnits'
]
},
1,
0
]
}
},
Unit6: {
$sum: {
$cond: [
{
$in: [
'Unit6',
'$member.rosterUnits'
]
},
1,
0
]
}
},
Unit7: {
$sum: {
$cond: [
{
$in: [
'Unit7',
'$member.rosterUnits'
]
},
1,
0
]
}
}
}
}, {
$project: {
_id: 0
}
}]
Query
because you want to count values that might not exists, you can make the groups manualy, and do conditional count
after the group you can do extra tranformation(if you really need the expected outpute exactly like that). Object to array, and map to give the field names(name,count)
Playmongo
aggregate(
[{"$unwind": "$member.rosterUnits"},
{"$group":
{"_id": null,
"Unit1":
{"$sum":
{"$cond": [{"$eq": ["$member.rosterUnits", "Unit1"]}, 1, 0]}},
"Unit2":
{"$sum":
{"$cond": [{"$eq": ["$member.rosterUnits", "Unit2"]}, 1, 0]}},
"Unit3":
{"$sum":
{"$cond": [{"$eq": ["$member.rosterUnits", "Unit3"]}, 1, 0]}},
"Unit4":
{"$sum":
{"$cond": [{"$eq": ["$member.rosterUnits", "Unit4"]}, 1, 0]}},
"Unit5":
{"$sum":
{"$cond": [{"$eq": ["$member.rosterUnits", "Unit5"]}, 1, 0]}},
"Unit6":
{"$sum":
{"$cond": [{"$eq": ["$member.rosterUnits", "Unit6"]}, 1, 0]}},
"Unit7":
{"$sum":
{"$cond": [{"$eq": ["$member.rosterUnits", "Unit7"]}, 1, 0]}}}},
{"$unset": ["_id"]},
{"$project":
{"result":
{"$map":
{"input": {"$objectToArray": "$$ROOT"},
"in": {"name": "$$this.k", "count": "$$this.v"}}}}}])
My Document looks something like this
{ _id: ObjectId("60b114b2415731001943b17f"),
processList:[
{ processName: 'Wood cutting',
createdAt: '2021-05-28T08:59:06.260Z',
updatedAt: '2021-05-28T08:59:06.260Z',
id: '60b0f0e9659a3b001c235300',
endTime: '2021-07-09T22:25:57.973Z',
isCompleted: false },
{ processName: 'Painting',
createdAt: '2021-05-28T13:32:02.441Z',
updatedAt: '2021-05-28T13:32:02.441Z',
id: '60b0f0e9659a3b001c235301',
endTime: 2021-05-28T17:05:06.067Z,
isCompleted: true },
{processName: 'Varnishing',
createdAt: '2021-05-28T09:46:33.169Z',
updatedAt: '2021-05-28T09:46:33.169Z',
id: '60b0f0e9659a3b001c235302',
endTime: 2021-05-28T20:05:06.067Z,
isCompleted: false }
],
companyId: '60b0a2b7b0beab001a068f8c',
customerId: '60b11289415731001943b17d',
productName: 'Queen size bed',
quantity: 1,
orderStartedTime: 2021-05-28T16:05:06.067Z,
estimatedEndTime: 2021-05-29T01:05:06.067Z,
createdAt: 2021-05-28T16:05:06.069Z,
updatedAt: 2021-07-09T22:20:58.019Z,
__v: 0,
percentageCompleted: 33.33333333333333 }
I'm trying to update the percentageCompleted and one of the process list's isCompleted true based on the id inside processList.
I ran this query but throws error
db.orders.findOneAndUpdate(
{
_id: ObjectId('60b114b2415731001943b17f')
},
[
{
$set: {"processList.$[element].isCompleted": true}
},
{
multi: true,
arrayFilters: [{ 'element.id': { $eq: "60b0f0e9659a3b001c235300" } }],
},
{
$set: {
percentageCompleted: {
$multiply: [
{
$divide: [{
$size: {
$filter: {
input: "$processList",
as: "process",
cond: { $eq: ["$$process.isCompleted", true] }
}
}
},
{ $size: "$processList" }]
}, 100
]
},
}
}
]
)
When I exclude the updation of array (isCompleted), the updation of percentageCompleted is getting calculated and set. Can someone help me how to proceed. Thanks in advance.
We can mix update operators with aggregate operators, if we need aggregate operators we do update it with pipeline update.
pipeline updates require MongoDB >=4.2
Query
map to update the processList
your $set from your query
Test code here
db.collection.update({
"_id": "60b114b2415731001943b17f"
},
[
{
"$set": {
"processList": {
"$map": {
"input": "$processList",
"in": {
"$cond": [
{
"$eq": [
"$$this.id",
"60b0f0e9659a3b001c235300"
]
},
{
"$mergeObjects": [
"$$this",
{
"isCompleted": true
}
]
},
"$$this"
]
}
}
}
}
},
{
"$set": {
"percentageCompleted": {
"$multiply": [
{
"$divide": [
{
"$size": {
"$filter": {
"input": "$processList",
"as": "process",
"cond": {
"$eq": [
"$$process.isCompleted",
true
]
}
}
}
},
{
"$size": "$processList"
}
]
},
100
]
}
}
}
])
Not possible. Aggregation is used only to fetch/read data.
You must work with 2 queries from server.
First to find the value to update using aggregate.
Then make another request to update the value.
This method will not work, if you are expecting multiple request at the same time trying to update the same document.
aggregation in nodejs resulting in nested json, can I get it without nesting, taking only one data _id from all collections. Is there any possibility to get the data without a nested json
I was trying aggregation in nodejs with the below code. I got the output as given in output session below. But I would like to get the output as expected output, since I cant use looping on looping
Student.aggregate([
{
$match: { name: 'abcd'}
},
{
$lookup:{
from:'teachers',
pipeline: [
{
$match: { name: 'pqrs' }
},
{
$project:{
"_id":1
}
}
],
as: "teacherLookup"
}
},
{
$lookup:
{
from:'subjects',
pipeline: [
{
$match: { name: 'computer' }
},
{
$project:{
"_id":1
}
}
],
as: "subjectLookup"
}
}
])
output
[
{
_id: '52301c7878965455d2a4',
teacherLookup: [ '5ea737412589688930' ],
subjectLookup: [ '5ea745821369999917' ]
}
]
I am expecting the output as (without nested json)
[
{
studentId: '5ea1c7878965455d2a4',
teacherId: '5ea737412589688930' ,
subjectId: '5ea745821369999917'
}
]
You can use $arrayElemAt to get the first element from the array.
Student.aggregate([
{
$match: { name: "abcd" },
},
{
$lookup: {
from: "teachers",
pipeline: [
{
$match: { name: "pqrs" },
},
{
$project: {
_id: 1,
},
},
],
as: "teacherId",
},
},
{
$lookup: {
from: "subjects",
pipeline: [
{
$match: { name: "computer" },
},
{
$project: {
_id: 1,
},
},
],
as: "subjectId",
},
},
{
$project: {
teacherId: { $arrayElemAt: ["$teacherId", 0] },
subjectId: { $arrayElemAt: ["subjectId", 0] },
},
}
]);
I am trying to get first date from inner array in mongodb object and add it to it's parent with aggregation. Example:
car: {
"model": "Astra",
"productions": [
"modelOne": {
"dateOfCreation": "2019-09-30T10:15:25.026+00:00",
"dateOfEstimation": "2017-09-30T10:15:25.026+00:00",
"someOnterInfo": "whatever"
},
"modelTwo": {
"dateOfCreation": "2017-09-30T10:15:25.026+00:00",
"dateOfEstimation": "2019-09-30T10:15:25.026+00:00",
"someOnterInfo": "whatever"
}
]
}
to be turned in
car: {
"model": "Astra",
"earliestDateOfEstimation": "2017-09-30T10:15:25.026+00:00",
"earliestDateOfCreation": "2017-09-30T10:15:25.026+00:00"
}
How can I achieve that?
I'm assuming that modelOne and modelTwo are unknown when you start your aggregation. The key step is to run $map along with $objectToArray in order to get rid of those two values. Then you can just use $min to get "earliest" values:
db.collection.aggregate([
{
$addFields: {
dates: {
$map: {
input: "$car.productions",
in: {
$let: {
vars: { model: { $arrayElemAt: [ { $objectToArray: "$$this" }, 0 ] } },
in: "$$model.v"
}
}
}
}
}
},
{
$project: {
_id: 1,
"car.model": 1,
"car.earliestDateOfEstimation": { $min: "$dates.dateOfEstimation" },
"car.earliestDateOfCreation": { $min: "$dates.dateOfCreation" },
}
}
])
Mongo Playground
EDIT:
First step can be simplified if there's always modelOne, 'modelTwo'... (fixed number)
db.collection.aggregate([
{
$addFields: {
dates: { $concatArrays: [ "$car.productions.modelOne", "$car.productions.modelTwo" ] }
}
},
{
$project: {
_id: 1,
"car.model": 1,
"car.earliestDateOfEstimation": { $min: "$dates.dateOfEstimation" },
"car.earliestDateOfCreation": { $min: "$dates.dateOfCreation" },
}
}
])
Mongo Playground (2)
I have changed one of the fields of my collection in mongoDB from an array of strings to an array of object containing 2 strings. New documents get inserted without any problem, but when a get method is called to get , querying all the documents I get this error:
Failed to decode 'Students'. Decoding 'photoAddresses' errored
with: readStartDocument can only be called when CurrentBSONType is
DOCUMENT, not when CurrentBSONType is STRING.
photoAddresses is the field that was changed in Students.
I was wondering is there any way to update all the records so they all have the same data type, without losing any data.
The old version of photoAdresses:
"photoAddresses" : ["something","something else"]
This should be updated to the new version like this:
"photoAddresses" : [{photoAddresses:"something"},{photoAddresses:"something else"}]
The following aggregation queries update the string array to object array, only if the array has string elements. The aggregation operator $map is used to map the string array elements to objects. You can use any of the two queries.
db.test.aggregate( [
{
$match: {
$expr: { $and: [ { $isArray: "$photo" },
{ $gt: [ { $size: "$photo" }, 0 ] }
]
},
"photo.0": { $type: "string" }
}
},
{
$project: {
photo: {
$map: {
input: "$photo",
as: "ph",
in: { addr: "$$ph" }
}
}
}
},
] ).forEach( doc => db.test.updateOne( { _id: doc._id }, { $set: { photo: doc.photo } } ) )
The following query works with MongoDB version 4.2+ only. Note the update operation is an aggregation instead of an update. See updateMany.
db.test.updateMany(
{
$expr: { $and: [ { $isArray: "$photo" },
{ $gt: [ { $size: "$photo" }, 0 ] }
]
},
"photo.0": { $type: "string" }
},
[
{
$set: {
photo: {
$map: {
input: "$photo",
as: "ph",
in: { addr: "$$ph" }
}
}
}
}
]
)
[EDIT ADD]: The following query works with version MongoDB 3.4:
db.test.aggregate( [
{
$addFields: {
matches: {
$cond: {
if: { $and: [
{ $isArray: "$photoAddresses" },
{ $gt: [ { $size: "$photoAddresses" }, 0 ] },
{ $eq: [ { $type: { $arrayElemAt: [ "$photoAddresses", 0 ] } }, "string" ] }
] },
then: true,
else: false
}
}
}
},
{
$match: { matches: true }
},
{
$project: {
photoAddresses: {
$map: {
input: "$photoAddresses",
as: "ph",
in: { photoAddresses: "$$ph" }
}
}
}
},
] ).forEach( doc => db.test.updateOne( { _id: doc._id }, { $set: { photoAddresses: doc.photoAddresses } } ) )