Statistics with Mongo DB - mongodb

Question

I have the following DB structure :
{
"uploadedAt": "2021-09-22T22:09:12.133Z",
"paidAt: "2021-09-30T22:09:12.133Z",
"amount": {
"currency": "EUR",
"expected": 70253,
"paid": 0
},
}
I would like to know how do I calculate the total amount that still need to be paid (expected - paid), and the average date between uploadedAt and paidAt. This for multiple records.
My function for getting the data is (the criteria should be updated to get this data).
const invoiceParams = new FindParams();
invoiceParams.criteria = { company: company._id }
const invoices = await this.findAll(invoiceParams);
FindAll function looks like:
async findAll(
params: FindParams,
ability?: Ability,
includeDeleted: boolean = false,
): Promise<Entity[]> {
let queryCriteria: Criteria = params.criteria;
let query: DocumentQuery<Entity[], Entity> = null;
if (!includeDeleted) {
queryCriteria = {
...queryCriteria,
deleted: { $ne: true },
};
}
try {
if (ability) {
ability.throwUnlessCan('read', this.entityModel.modelName);
queryCriteria = {
...toMongoQuery(ability, this.entityModel.modelName),
...queryCriteria,
};
}
query = this.entityModel.find(queryCriteria);
if (params.populate) {
query = query.populate(params.populate);
}
if (params.sort) {
query = query.sort(params.sort);
}
if (params.select) {
query = query.select(params.select);
}
return query.exec();
} catch (error) {
if (error instanceof ForbiddenError) {
throw new ForbiddenException(error.message);
}
throw error;
}
}
Update:
const paymentTime = await this.invoiceModel.aggregate([
{
$group: {
_id: "$account",
averageSpread: { $avg: { $subtract: ["$paidAt", "$uploadedAt"] } },
count: { $sum: 1 }
}
}
]);

Answer 1

Try this aggregation pipeline:
db.invoiceParams.aggregate([
{
$set: {
expectedPaid: { $subtract: ["$amount.expected", "$amount.paid"] },
averageDate: { $toDate: { $avg: [{ $toLong: "$uploadedAt" }, { $toLong: "$paidAt" }] } }
}
}
])