Develop Reference

MongoDB : - Merge object with same key into one

I am trying to merge an object inside an array with the same date but with a different key name for the status key.
I have 2 collections users and canteens
The query I am trying to get the result but am not able to figure out how to merge the object with the same Date
OUTPUT
User.aggregate([
{ $sort: { workerId: 1 } },
{
$lookup: {
from: "canteens",
localField: "_id",
foreignField: "employeeId",
pipeline: [
{
$match: {
Date: {
$gte: new Date(fromDate),
$lte: new Date(toDate),
},
},
},
{
$project: {
Date: 1,
status: 1,
},
},
],
as: "canteens",
},
},
{
$project: {
_id: 1,
workerId: 1,
workerFirstName: 1,
workerSurname: 1,
workerDepartment: 1,
workerDesignation: 1,
locationName: 1,
canteenData: "$canteens",
},
},
]);
[
{
"_id": "60e6fd3616dd663e84a925e2",
"workerFirstName": "Firstaname",
"workerSurname": "lastname",
"workerId": "1",
"locationName": "location",
"workerDesignation": "designation",
"workerDepartment": "department",
"canteenData": [
{
"_id": "63b285b9e92eee614feb7be1",
"status": "LUNCH",
"Date": "2023-01-02T00:00:00.000Z"
},
{
"_id": "63b2db8db10c24487201e0a2",
"status": "DINNER",
"Date": "2023-01-02T00:00:00.000Z"
},
{
"_id": "63b39b247adbeb50bfbe3503",
"status": "BREAK FAST",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b3d248c076184fb07ff2c4",
"status": "LUNCH",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b42b8ccb57a4cb7af34015",
"status": "DINNER",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b4ef71e038498fe6634506",
"status": "BREAK FAST",
"Date": "2023-01-04T00:00:00.000Z"
}
]
},
{
"_id": "60e6fd3616dd663e84a925e2",
"workerFirstName": "Firstaname1",
"workerSurname": "lastname1",
"workerId": "2",
"locationName": "location",
"workerDesignation": "designation",
"workerDepartment": "department",
"canteenData": [
{
"_id": "63b285b9e92eee614feb7be1",
"status": "LUNCH",
"Date": "2023-01-02T00:00:00.000Z"
},
{
"_id": "63b2db8db10c24487201e0a2",
"status": "DINNER",
"Date": "2023-01-02T00:00:00.000Z"
},
{
"_id": "63b39b247adbeb50bfbe3503",
"status": "BREAK FAST",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b3d248c076184fb07ff2c4",
"status": "LUNCH",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b42b8ccb57a4cb7af34015",
"status": "DINNER",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b4ef71e038498fe6634506",
"status": "BREAK FAST",
"Date": "2023-01-04T00:00:00.000Z"
}
]
}
]
The output I am trying to get
[
{
"_id": "60e6fd3616dd663e84a925e2",
"workerFirstName": "Firstanem",
"workerSurname": "lastname",
"workerId": "1",
"locationName": "location",
"workerDesignation": "designation",
"workerDepartment": "department",
"canteenData": [
{
"_id": "63b285b9e92eee614feb7be1",
"status1": "LUNCH",
"status2": "DINNER",
"Date": "2023-01-02T00:00:00.000Z"
},
{
"_id": "63b39b247adbeb50bfbe3503",
"status1": "BREAK FAST",
"status2": "LUNCH",
"status3": "DINNER",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b4ef71e038498fe6634506",
"status1": "BREAK FAST",
"Date": "2023-01-04T00:00:00.000Z"
}
]
},
{
"_id": "60e6fd3616dd663e84a925e2",
"workerFirstName": "Firstanem1",
"workerSurname": "lastname1",
"workerId": "2",
"locationName": "location",
"workerDesignation": "designation",
"workerDepartment": "department",
"canteenData": [
{
"_id": "63b285b9e92eee614feb7be1",
"status1": "LUNCH",
"status2": "DINNER",
"Date": "2023-01-02T00:00:00.000Z"
},
{
"_id": "63b39b247adbeb50bfbe3503",
"status1": "BREAK FAST",
"status2": "LUNCH",
"status3": "DINNER",
"Date": "2023-01-03T00:00:00.000Z"
},
{
"_id": "63b4ef71e038498fe6634506",
"status1": "BREAK FAST",
"Date": "2023-01-04T00:00:00.000Z"
}
]
}
]

One option is to add 2 steps into your $lookup pipeline aggregation:
{$group: {
_id: "$Date",
_idVal: {$first: "$_id"},
data: {$addToSet: "$status"}
}},
{$replaceRoot: {
newRoot: {
$mergeObjects: [
{_id: "$_idVal", Date: "$_id"},
{$arrayToObject: {
$reduce: {
input: "$data",
initialValue: [],
in: {$concatArrays: [
"$$value",
[{k: {$concat: [
"status",
{$toString: {$add: [{$size: "$$value"}, 1]}}
]},
v: "$$this"}]
]}
}
}}
]
}
}}
See how it works on the playground example

It's not easy to create status1, status2, ... variables dynamically + how do we know BREAK FAST should be status1 and not status2.
Alternative solution: We $group inside correlated subqueries and push all status values into an array
db.users.aggregate([
{
"$lookup": {
"from": "canteens",
"localField": "_id",
"foreignField": "employeeId",
pipeline: [
{
// Put your custom filters here
$match: {}
},
{
$group: {
_id: "$Date",
//pick "first" canteens _id
id: {
$first: "$_id"
},
status: {
$push: "$status"
}
}
},
{
$project: {
_id: "$id",
Date: "$_id",
status: 1
}
},
],
as: "canteenData",
}
}
])
MongoPlayground

MongoDB - Structure an array without using key field in Aggregration

I'm having an issue with making count for items returned from an array without assuming or using those fields in my aggregration.
Data structure looks like this:
[
{
"_id": "1",
"title": "Vanella Icream",
"contain": "sugar",
"details": [
{
"flavour": "Vanella"
},
{
"weight": "10KG"
},
{
"sugar": "15KG"
}
]
},
{
"_id": "2",
"title": "Pretzels",
"contain": "salt",
"details": [
{
"flavour": "Wheat"
},
{
"weight": "10KG"
},
{
"sugar": "15KG"
}
]
},
{
"_id": "3",
"title": "Rasmalai Icream",
"contain": "sugar",
"details": [
{
"flavour": "Vanella"
},
{
"weight": "15KG"
},
{
"sugar": "12KG"
}
]
},
{
"_id": "4",
"title": "Vanella Icream",
"contain": "sugar",
"details": [
{
"flavour": "Vanella"
},
{
"weight": "15KG"
},
{
"sugar": "12KG"
}
]
}
]
Output I want:
[
{
"details": {
"flavour": {
"Vanella": 3, //Number of times Vanella present in each document.
"Wheat": 1,
},
"weight": {
"10KG": 2,
"15KG": 2
},
"sugar": {
"12KG": 2,
"15KG": 2
}
}
}
]
Query:
db.collection.aggregate([
{
"$unwind": {
"path": "$details"
}
},
{
"$replaceRoot": {
"newRoot": {
"$mergeObjects": [
"$details",
"$$ROOT"
]
}
}
},
{
"$facet": {
"flavour": [
{
"$group": {
"_id": "$flavour",
"sum": {
"$sum": 1
}
}
},
{
"$addFields": {
"flavour": "$_id"
}
},
{
"$project": {
"_id": 0
}
}
],
"weight": [
{
"$group": {
"_id": "$weight",
"sum": {
"$sum": 1
}
}
},
{
"$addFields": {
"weight": "$_id"
}
},
{
"$project": {
"_id": 0
}
}
]
}
},
{
"$addFields": {
"flavour": {
"$reduce": {
"input": {
"$filter": {
"input": {
"$map": {
"input": "$flavour",
"as": "w",
"in": {
"$cond": [
{
"$ne": [
"$$w.flavour",
null
]
},
{
"$let": {
"vars": {
"o": [
[
"$$w.flavour",
"$$w.sum"
]
]
},
"in": {
"$arrayToObject": "$$o"
}
}
},
null
]
}
}
},
"as": "f",
"cond": {
"$ne": [
"$$f",
null
]
}
}
},
"initialValue": {},
"in": {
"$let": {
"vars": {
"d": "$$value",
"p": "$$this"
},
"in": {
"$mergeObjects": [
"$$d",
"$$p"
]
}
}
}
}
},
"weight": {
"$reduce": {
"input": {
"$filter": {
"input": {
"$map": {
"input": "$weight",
"as": "w",
"in": {
"$cond": [
{
"$ne": [
"$$w.weight",
null
]
},
{
"$let": {
"vars": {
"o": [
[
"$$w.weight",
"$$w.sum"
]
]
},
"in": {
"$arrayToObject": "$$o"
}
}
},
null
]
}
}
},
"as": "f",
"cond": {
"$ne": [
"$$f",
null
]
}
}
},
"initialValue": {},
"in": {
"$let": {
"vars": {
"d": "$$value",
"p": "$$this"
},
"in": {
"$mergeObjects": [
"$$d",
"$$p"
]
}
}
}
}
}
}
},
{
"$project": {
"details": "$$ROOT"
}
}
])
Here I'm trying to get the flavour and weight with their count, with manually adding those fields in $filter stage. I want to do it without assuming those keys. So, even if there is 20 items present in array details it will map those items and shows me output with their counts respectively.
I hope you guys understand.
Playground:https://mongoplayground.net/p/j1mzgWvcmvd

You need to change the schema, the thing you want to do is easy, and both those queries are so complicated and slow, even the second that is much smaller has 2 $unwind and 3 $group with 3 $arrayToObject and 8 stages total because of the schema and the schema of the answer.
Don't store data in the keys of the documents, people that are new to MongoDB do those, i was doing it also, but it makes all things harder.(i can't say like never do it but you dont need it here)
Your schema should be something like
{
"_id": "2",
"title": "Pretzels",
"contain": "salt",
"details": [
{
"type" : "flavour",
"value" : "Wheat"
},
{
"type" : "weight",
"value" : "10KG"
},
{
"type" : "sugar",
"value" : "15KG"
}
]
}
See this example
Converts your schema, to the new schema and produce the results you
want but without data in keys (the first part you wouldnt need it you would need only the bellow query if you had that schema from start)
Query with the new Schema (no data in keys)
[{"$unwind": { "path": "$details"}},
{"$replaceRoot": {"newRoot": "$details"}},
{
"$group": {
"_id": {
"type": "$type",
"value": "$value"
},
"sum": {"$sum": 1}
}
},
{
"$replaceRoot": {
"newRoot": {"$mergeObjects": ["$_id","$$ROOT"]}
}
},
{"$project": {"_id": 0}},
{
"$group": {
"_id": "$type",
"values": {
"$push": {
"value": "$value",
"sum": "$sum"
}
}
}
},
{"$addFields": {"type": "$_id"}},
{"$project": {"_id": 0}}
]
MongoDB operators are not made to support for data in keys or dynamic keys(uknown keys) (to do it you do complicated things like the above)
If you want to change your schema, either do it with update in the database,
Or take the documents to the application and do it with javascript, and re-insert.
Even if you solve this question in the next one, you will have again problems.

I'm the guy from Mongodb Forum:
Try this out https://mongoplayground.net/p/tfyfpIkHilQ

How to add name in JSONPATH

I have an array like this
{
"activities": [
{
"activityId": "60f672b20f38640008a6c29b",
"_id": "610cb887b149cb00095e1eb6",
"trackingProgress": [
{
"_id": "610cb8ee541fea0009189c36",
"dateRecorded": "2021-07-16T00:00:00.000Z",
"items": [
{
"_id": "610cb8ee541fea0009189c37",
"feelingType": "Satisfied",
"times": 2
}
]
},
{
"_id": "611358300fea490008d56ea7",
"dateRecorded": "2021-08-10T00:00:00.000Z",
"items": [
{
"_id": "6113583b0fea490008d56eae",
"feelingType": "Neutral",
"times": 1
}
]
},
{
"_id": "611b6068fed9100009a4f689",
"dateRecorded": "2021-08-17T00:00:00.000Z",
"items": [
{
"_id": "611b6068fed9100009a4f68a",
"feelingType": "Satisfied",
"times": 4
}
]
}
],
"title": "Losing & Managing Weight",
"description": "Losing weight",
"order": null,
"daysOfWeek": [
"tuesday"
],
"reminderTimeAt": "09:00 am",
"type": "Custom",
"progressOverview": {
"notSatisfied": 0,
"neutral": 1,
"satisfied": 6
}
}
]
}
I use JSONPATH to get _id in items
$.activities.[*].trackingProgress.[*].items[*].[_id]
it return an array like this
[
"610cb8ee541fea0009189c37",
"6113583b0fea490008d56eae",
"611b6068fed9100009a4f68a"
]
But, i want to keep the "_id", something like :
[
"_id":"610cb8ee541fea0009189c37",
"_id":"6113583b0fea490008d56eae",
"_id":"611b6068fed9100009a4f68a"
]
How can i do that?? Thank you a lots, i search internet but i found nothing

If you use map, you can get an array of items that each have an _id and value.
let result = [
"610cb8ee541fea0009189c37",
"6113583b0fea490008d56eae",
"611b6068fed9100009a4f68a"
].map(i => ({"_id": i}))
Results in:
[{ _id: "610cb8ee541fea0009189c37" },
{ _id: "6113583b0fea490008d56eae" },
{ _id: "611b6068fed9100009a4f68a" }]

aggregate match returns null with $gte and $lt

I am using the following code to retrieve the data from mongodb. Somehow when I added the $match to the code it returns empty set. Without it I get my results fine so there is no any other error. What can be the error in $match . How can I fix it ?
This is the code in my API?
postSchemaModel.aggregate([{
"$geoNear": {
"near": { "type": "Point", "coordinates": [parseFloat(long), parseFloat(lat), ] },
"distanceField": "dist.calculated",
"maxDistance": parseInt(maxDistance),
"includeLocs": "dist.location",
"spherical": true
}
},
// mactchString,
{
"$match": {
"createdAt": {
"$gte": '2020-07-15 23:54:38.673665',
"$lt": '2020-06-15 23:54:38.673665'
}
}
},
{ "$limit": limit },
{ "$skip": startIndex },
{ "$sort": { "createdAt": -1 } },
{
"$lookup": {
"from": userSchemaModel.collection.name,
"localField": "user_id",
"foreignField": "_id",
"as": "user_id"
}
},
{
"$project": {
"post_data": 1,
"likes": 1,
"commentsCount": 1,
"post_img": 1,
"isUserLiked": 1,
"usersLiked": 1,
'exp_date': 1,
"has_img": 1,
"user_id": {
"img": "$user_id.img",
"_id": "$user_id._id",
"user_name": "$user_id.user_name",
"bday": "$user_id.bday",
"imagesource": "$user_id.imagesource",
"fb_url": "$user_id.fb_url",
},
"typology": 1,
"geometry": 1,
"category": 1,
"created": 1,
"createdAt": 1,
"updatedAt": 1,
}
},
]).then(async function(posts) {
//some code here
}
});
The following is a sample post from mongodb
What can be the error here. How can I fix it ?

Wrap the date field in new Date() similar to this
"$match": {
"createdAt": {
"$gte": new Date('2020-07-15T23:54:38.673Z'),
"$lt": new Date('2020-06-15T23:54:38.673Z')
}
}
Check this Q & A.

Wrong Result by $lookup mongodb

I am using $lookup to get the data by joining data from two or three collections, Below is my aggregate query.
let condition = {status:{$ne:config.PROJECT_STATUS.completed}, assignId:mongoose.Types.ObjectId(req.params.id)};
Project.aggregate([
{
"$match": condition
},
{
"$group": { "_id": "$_id" }
},
{
"$lookup": {
"from": "worksheets",
"let": { "projectId": "$_id" },
"pipeline": [
{
"$match": { "$expr": { "$eq": ["$projectId", "$$projectId"] } }
},
{
"$group": { "_id": "$projectId", "totalHours": { "$sum": "$hours" } }
},
{
"$lookup": {
"from": "projects",
"let": { "projectId": "$_id" },
"pipeline": [
{ "$match": { "$expr": { "$eq": ["$_id", "$$projectId"] } } },
{
"$lookup": {
"from": "users",
"let": { "developers": "$developers" },
"pipeline": [
{ "$match": { "$expr": { "$in": ["$_id", "$$developers"] } } },
{ "$project":{"firstName":1,"lastName":1}}
],
"as": "developers"
}
},
{
"$lookup": {
"from": "billing_accounts",
"let": { "upworkId": "$upworkId" },
"pipeline": [
{ "$match": { "$expr": { "$eq": ["$_id", "$$upworkId"] } } },
{"$project":{"name":1,"username":1}}
],
"as": "upworkId"
}
},
{
"$project": {
"projectName": 1, "upworkId": 1, "status": 1, "developers": 1, "hoursApproved": 1
}
}
],
"as": "project"
}}
],
"as": "projects"
}
}
])
And it is giving me the below result:
[
{
"_id": "5c188a9959f6cf1258f4cb01",
"projects": [
{
"_id": "5c188a9959f6cf1258f4cb01",
"totalHours": 8,
"project": [
{
"_id": "5c188a9959f6cf1258f4cb01",
"hoursApproved": 192,
"developers": [
{
"_id": "5c0a29e597e71a0d28b910aa",
"lastName": "kumar",
"firstName": "Amit"
}
],
"projectName": "Jims fitness",
"status": "ongoing",
"upworkId": [
{
"_id": "5c17a1cec1a7681f7c54bb2d",
"name": "Heena Ln",
"username": "heena_ln"
}
]
}
]
}
]
},
{
"_id": "5c17a253c1a7681f7c54bb2f",
"projects": []
}
]
But what i want to get is:
[
{
"_id": "5c188a9959f6cf1258f4cb01",
"projects": [
{
"_id": "5c188a9959f6cf1258f4cb01",
"totalHours": 0,
"project": [
{
"_id": "5c188a9959f6cf1258f4cb01",
"hoursApproved": 192,
"developers": [
{
"_id": "5c0a29e597e71a0d28b910aa",
"lastName": "kumar",
"firstName": "Amit"
}
],
"projectName": "Project1",
"status": "ongoing",
"upworkId": [
{
"_id": "5c17a1cec1a7681f7c54bb2d",
"name": "Heena Ln",
"username": "heena_ln"
}
]
}
]
}
]
},
{
"_id": "5c17a253c1a7681f7c54bb2f",
"projects": [
{
"_id": "5c17a253c1a7681f7c54bb2f",
"totalHours": 0,
"project": [
{
"_id": "5c17a253c1a7681f7c54bb2f",
"hoursApproved": 192,
"developers": [
{
"_id": "5c0a29e597e71a0d28b910a9",
"lastName": "kumar",
"firstName": "Rajat"
}
],
"projectName": "project2",
"status": "ongoing",
"upworkId": [
{
"_id": "5c17a1cec1a7681f7c54bb2d",
"name": "Heena Ln",
"username": "heena_ln"
}
]
}
]
}
]
}
]
As you can see that now i have totalHours equals to 0 instead of empty array and have the project details.
Actually I have four collections: projects, worksheets, users and billings and i am executing aggregate query on the projects collection to get the projects of a project manager and for this i am also joining worksheets collection to get the data for how many hours the employees worked on this project, because worksheets collection contains the projectId, userId and hours.
Query: You can see in the result that, i am getting the empty array of projects, this is because i don't have any record of second project projectId into the worksheet collection, so for this it is giving me empty array, but i want to get the projects details as it is and totalHours equals to 0.