I have this Event array but can't figure out how to query into the 'guests' nested array and do two things.
count the number of guests
count the number of attended guests (marked 'Y')
{ _id: new ObjectId('1'),
name: event1,
guests: [
{
phone: +12222222222,
_id: new ObjectId,
attended: 'Y'
},
{
phone: +12344466666,
_id: new ObjectId,
attended: 'Y'
},
{ phone: +11234567890,
_id: new ObjectId,
attended:
},
{
phone: +14443332222,
_id: new ObjectId,
attended: 'Y'
},
{ phone: +19090909090,
_id: new ObjectId
attended:
}
],
},
{ _id: new ObjectId('2'),
name: event2,
guests: [
{
phone: +11111111111,
_id: new ObjectId,
attended:
},
{
phone: +12222222222,
_id: new ObjectId,
attended: 'Y'
},
{
phone: +133333333333,
_id: new ObjectId,
attended: 'Y'
}
],
},
My code below is on its 20th iteration without getting any closer.
const event = await Event.findById(req.params.id);
For MongoDB query, you can use $size for calculating the size of the array field and $filter to filter specific document(s) that matched the criteria in the projection.
db.collection.find({
_id: "1"
},
{
_id: 1,
name: 1,
guests: 1,
totalGuests: {
$size: "$guests"
},
attendedGuests: {
$size: {
"$filter": {
input: "$guests",
cond: {
$eq: [
"$$this.attended",
"Y"
]
}
}
}
}
})
Sample Mongo Playground
Yong Shun helped above but didn't get 100% of the way -- here is the full answer in case anyone encounters something like this in the future:
module.exports.showEvent = async (req, res) => {
const event = await Event.findById(req.params.id).populate('artist');
const { guest_id } = req.cookies;
let totalGuests = 0;
let attendedGuests = 0;
const eventData = await Event.aggregate([
{
"$match": {
"_id": objectId(req.params.id)
}
},
{
$project: {
_id: 1,
name: 1,
guests: 1,
totalGuests: { $cond: { if: { $isArray: "$guests" }, then: { $size: "$guests" }, else: "NA" } },
attendedGuests: {
$size: {
$filter: {
input: "$guests",
as: "guest",
cond: {
$and: [{
$eq: ["$$guest.attended", "Y"]
}]
}
}
}
}
}
}
])
if (eventData && Array.isArray(eventData) && eventData.length > 0) {
totalGuests = eventData[0].totalGuests;
attendedGuests = eventData[0].attendedGuests;
}
if (!event) {
req.flash('error', 'Cannot find that Event');
return res.redirect('/events');
}
res.render('events/show', { event, eventData });
console.log(totalGuests, attendedGuests);
};
Related
I have a MongoDB Model which consist of array of members as obejcts.
const guestSchema = new mongoose.Schema({
salutation: {
type: String,
},
members: [membersSchema],
user: {
type: mongoose.Schema.ObjectId,
ref: 'User',
},
});
Members Schema:
const membersSchema = new mongoose.Schema({
name: String,
status: {
type: String,
enum: ['regular', 'helper'],
default: 'regular',
},
});
I want to achieve of doing an update in case documet with given ID exist or push to an array in case ID with document in array does not exist. I use aggregation pipeline, however I am not able to achieve pushing new document to array. Why can't I use push after else statement like this.
const subDocumentToUpsert = { 'name': mem.name, 'status': mem.status, '_id': ObjectId(mem.id)}
const subDocumentNoID = { 'name': mem.name, 'status': mem.status}
await Guest.findOneAndUpdate(
{ "_id": req.params.id },
[
{
$set: {
members: {
$cond: {
if: { $in: [subDocumentToUpsert._id, '$members._id'] },
then: {
$map: {
input: '$members',
as: 'sub_document',
in: {
$cond: {
if: { $eq: ['$$sub_document._id', subDocumentToUpsert._id] },
then: subDocumentToUpsert,
else: '$$sub_document',
},
},
},
},
else: {
$push: {
subDocumentNoID
},
},
},
},
},
},
},
]);
What is the best way of doing so? Thank you
You can do as follow:
db.collection.update({
_id: {
$in: [
1,
2
]
}
},
[
{
$set: {
members: {
$cond: {
if: {
$in: [
5,
"$members._id"
]
},
then: {
$map: {
input: "$members",
as: "sub",
in: {
$cond: {
if: {
$eq: [
"$$sub._id",
5
]
},
then: {
_id: 5,
status: "regular_updated",
name: "Negan_updated"
},
else: "$$sub"
},
},
},
},
else: {
$concatArrays: [
"$members",
[
{
_id: 5,
status: "regular_upserted",
name: "Negan_upserted"
}
]
]
}
}
}
}
}
}
],
{
multi: true
})
Explained:
Check if _id:5 exist in the subobject and update via $map/$cond only the object that has the _id:5.
In case there is no _id:5 add the new object to the array with $concatArrays.
Playground
With MongoDB aggregate, how do you lookup child documents from an array on the parent document and match a field on the child to a value?
I want to lookup the ShopItems for a Shop. And I only want the ShopItems that are not kidFriendly.
Details:
Let's say I have Shops collection
Shop Schema
{
shopItems: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'ShopItem',
},
],
}
And a shop can have multiple Shop Items:
ShopItem Schema
[
itemName: { type: String },
kidFriendly: { type: Boolean, default: false },
]
I want to lookup the ShopItems for a Shop. And I only want the ShopItems that are not kidFriendly.
I tried
const result3 = await Shop.aggregate([
{
$match: {
_id: mongoose.Types.ObjectId('623ae52ba5b1af0004e1c4ec'),
},
},
{
$lookup: {
from: ShopItem.collection.collectionName,
pipeline: [
{
$match: {
kidFriendly: { $ne: true },
_id: { $in: '$shopItems' },
},
},
],
as: 'adultOnlyItems',
},
},
]);
but I get an error:
$in needs an array.
Example data
// shops
[
{
_id: ObjectId('623ae52ba5b1af0004e1c4ec'),
shopItems: [ObjectId('631e6b133b688a0004a17265'), ObjectId('62f4cc974a255f00044c01b5'), ObjectId('625ffc48eec7b20004c9294c')]
},
{
_id: ObjectId('623ae52ba5b1af0004e1c4eb'),
shopItems: [ObjectId('631e6b133b688a0004a17263')]
}
]
//shop items
[
{
_id: ObjectId('631e6b133b688a0004a17265'),
itemName: "Barbie",
kidFriendly: true
},
{
_id: ObjectId('62f4cc974a255f00044c01b5'),
itemName: "Alcohol",
kidFriendly: false
},
{
_id: ObjectId('625ffc48eec7b20004c9294c'),
itemName: "Glass Vase",
kidFriendly: false
},
{
_id: ObjectId('631e6b133b688a0004a17263'),
itemName: "Beach Ball",
kidFriendly: true
}
]
When you use $lookup with pipeline, you need to have the let to store the field value from shops into variable. And use the $expr operator as well.
db.shops.aggregate([
{
$match: {
_id: mongoose.Types.ObjectId('623ae52ba5b1af0004e1c4ec')
}
},
{
$lookup: {
from: ShopItem.collection.collectionName,
let: {
shopItems: "$shopItems"
},
pipeline: [
{
$match: {
$expr: {
$and: [
{
$ne: [
"$kidFriendly",
true
]
},
{
$in: [
"$_id",
"$$shopItems"
]
}
]
}
}
}
],
as: "adultOnlyItems"
}
}
])
Demo # Mongo Playground
Reference
Join Conditions and Subqueries on a Joined Collection
I tried to use aggregate to find out each product's monthly sales in my order , but I ran into a problem.
Here's my data structures.
Order.model.ts
const OrderSchema: Schema = new Schema(
{
userId: {
type: String,
require: true,
},
products: [
{
product: {
_id: {
type: String,
},
title: {
type: String,
},
desc: {
type: String,
},
img: {
type: String,
},
categories: {
type: Array,
},
price: {
type: Number,
},
createdAt: {
type: String,
},
updatedAt: {
type: String,
},
size: {
type: String,
},
color: {
type: String,
},
},
quantity: {
type: Number,
default: 1,
},
},
],
quantity: {
type: Number,
},
total: {
type: Number,
},
address: {
type: String,
require: true,
},
status: {
type: String,
default: 'pending',
},
},
{ timestamps: true },
);
Order-service.ts
public async getIncome(productId?: string) {
const date = new Date();
const lastMonth = new Date(date.setMonth(date.getMonth() - 1));
const previousMonth = new Date(new Date().setMonth(lastMonth.getMonth() - 1));
//const lastYear = new Date(date.setFullYear(date.getFullYear() - 1));
const income = await this.order.aggregate([
{
$match: {
createdAt: { $gte: lastMonth },
...(productId && {
products: { $elemMatch: { product: { _id: productId } } },
}),
},
},
{
$project: {
month: { $month: '$createdAt' },
sales: '$total',
},
},
{
$group: {
_id: '$month',
total: { $sum: '$sales' },
},
},
]);
return income;
}
When I calculate whole sales without productId , it went well , I tried to use elemMatch to find productId , but it won't work , did I miss something ?
Try $unwind "products" array first, then apply $match:
const income = await this.order.aggregate([
{
$unwind: '$products'
},
{
$match: {
createdAt: { $gte: lastMonth },
product: { _id: productId },
},
},
{
$project: {
month: { $month: '$createdAt' },
sales: '$total',
},
},
{
$group: {
_id: '$month',
total: { $sum: '$sales' },
},
},
]);
Situation :
I have a like button and I wish that when a user clicks on like the like in the database:
Increment if the user didn't yet like it (like with +1 and add user id from the likedBy array)
Decrease if the user already liked it (like - 1 and remove the used id from the likedBy array)
Code:
the controller :
exports.likeIdea = (req,res,next) => {
const userId = getUserId(req)
Ideas.updateOne({ _id: req.params.id}, {
$set: {
like: {
$cond: [ {$in: [userId, "$likedBy"]}, { $inc: { like: +1 } } , { $inc: { like: -1 } } ]
},
likedBy: {
$cond: [ {$in: [userId, "$likedBy"]}, { $pull: { likedBy: userId } } , { $push: { likedBy: userId } } ]
},
_id: req.params.id
}
})
.then(() => res.status(200).json({ message: 'Success'}))
.catch(error => {
res.status(400).json({ error })
});
};
the schema
const ideaSchema = mongoose.Schema({
name: { type: String, required: true},
sumup: { type: String, required: true },
description: { type: String, required: true},
published: {type: Boolean, required: true},
like: {type: Number, required: true},
likedBy: {type: [String]},
author: {type: String, required: true},
dislike: {type: Number, required: true},
dislikedBy: {type: [String]},
imgUrl: {type: String, required: true}
});
the error :
CastError: Cast to Number failed for value "{ '$cond': [ { '$in': [Array] }, { '$inc': [Object] }, { '$inc': [Object] } ] }" at path
"like" [...] {messageFormat: undefined, stringValue: '"{
'$cond': [ { '$in': [Array] }, { '$inc': [Object] }, { '$inc':
[Object] } ] }"', kind: 'Number', value: {…}, path: 'like', …}
The regular update query can not allow to use internal fields and aggregation operators like $cond, so you can't do this operation with regular update query,
You can try with update with aggregation pipeline starting from MongoDB 4.2,
instead of $inc you can use $add operator in aggregation update
instead of $pull you can use $filter to remove specific user
instead of $push you can use $concatArrays operator
exports.likeIdea = (req,res,next) => {
const userId = getUserId(req)
Ideas.updateOne({ _id: req.params.id},
[{
$set: {
like: {
$cond: [
{ $in: [userId, "$likedBy"] },
{ $add: ["$like", 1] },
{ $add: ["$like", -1] }
]
},
likedBy: {
$cond: [
{ $in: [userId, "$likedBy"] },
{
$filter: {
input: "$likedBy",
cond: { $ne: ["$$this", userId] }
}
},
{ $concatArrays: ["$likedBy", [userId]] }
]
}
}
}]
).then(() => res.status(200).json({ message: 'Success'}))
.catch(error => {
res.status(400).json({ error })
});
};
Playground
I have "Offers" and "Requests" collections, I need to get all offers that user made, group them by requests and find the lowest "Offer.price" on each request, each offer has requestId field.
I am using aggregate to solve this,
db.Offer.aggregate([{
$match: {
ownerId: mongoose.Types.ObjectId(req.params.ownerId)
}
},
{
$group: {
_id: "$requestId",
price: {
$min: "$price"
}
}
}
])
and This is what i get :
[ { _id: 5dc47241af1406031489c65c, price: 14 },
{ _id: 5dc47241af1406031489c653, price: 3 },
{ _id: 5dc47241af1406031489c656, price: 5 },
{ _id: 5dc8add63f73953ff408f962, price: 6 },
{ _id: 5dc8add63f73953ff408f969, price: 22 },
{ _id: 5dc47241af1406031489c658, price: 1 } ]
Now I want to populate these with rest of the data from "Offer"
const OfferSchema = new Schema({
requestId: {
type: Schema.Types.ObjectId,
ref: 'Request'
},
ownerId: {
type: Schema.Types.ObjectId,
required: true,
ref: 'User'
},
price: {
type: Number,
required: true
},
createdAt: {
type: Date,
default: Date.now
},
isBest: {
type: Boolean,
default: false
},
isWinner: {
type: Boolean,
default: false,
}
});
What would be best way to do something like this?
Thank you for your help!
Consider the following dataset:
db.dum.insert({ownerId:1, requestId:'a', price:3, createdAt:3, isWinner:true})
db.dum.insert({ownerId:1, requestId:'a', price:1, createdAt:1, isWinner:false})
db.dum.insert({ownerId:1, requestId:'a', price:2, createdAt:2, isWinner:true})
db.dum.insert({ownerId:1, requestId:'b', price:4, createdAt:2, isWinner:true})
db.dum.insert({ownerId:1, requestId:'b', price:5, createdAt:1, isWinner:false})
db.dum.insert({ownerId:2, requestId:'b', price:5, createdAt:1, isWinner:false})
You could use $reduce
Here, for a grouping id, we keep all matching documents as an array (candidates).
On the project stage, for each group we iterate through the array, and reduce it to the minimal element found (by price that is)
db.dum.aggregate([{
$match: {
ownerId: 1
}
},
{
$group: {
_id: "$requestId",
candidates: { $push:'$$ROOT'}
}
},
{
$project:{
item: {
$reduce: {
input: '$candidates',
initialValue: '$candidates.0',
in: {
$cond: {
if: {
$lt: ['$$value.price', '$$this.price']
},
then:'$$value',
else:'$$this'
}
}
}
}
}
},
{
$replaceRoot:{newRoot:'$item'}
}
]).toArray()
output:
[
{
"_id" : ObjectId("5ddcc8e0eb1f0217802fb507"),
"ownerId" : 1,
"requestId" : "b",
"price" : 4,
"createdAt" : 2,
"isWinner" : true
},
{
"_id" : ObjectId("5ddcc8e0eb1f0217802fb505"),
"ownerId" : 1,
"requestId" : "a",
"price" : 1,
"createdAt" : 1,
"isWinner" : false
}
]