I am working on aggregation to perform some analytics on an Orders object, I want to get the total price from every order from the previous month, and the total from this month, I tried passing in the $match parameter, with the appropriate time conditionals but it's not aggregating any of the data. even though if I perform a countDocuments query with the same time conditionals I get a number of documents returned.
const totalThis = await Order.aggregate([
{
$match: {
// should cut the amount of orders off at the beginning of the current month
createdAt: { $gte: thisMonth.getMonth() + 1 },
},
},
{
$group: {
// using $group, _id has to be there or it doesnt
// return anything, though we dont need an _id
_id: null,
total: {
$sum: "$totalPrice",
},
},
},
]);
res.status(200).json({
lastMonth: lastMonthSales,
thisMonth: thisMonthSales,
totalSalesLast: totalLast,
totalSalesThis: totalThis,
});
In my Postman request, lastMonth returns 0, so it would make sense that the array returned to totalSalesLast would be empty, however thisMonth returns 5 documents, so it should work. Obviously, if I remove the $match conditional it will aggregate all the documents, but that's because it's doing ALL the documents and not actually filtering.
To query the document with createdAt in specific month, your $match stage should be as below:
$month - Take the month value from createdAt.$eq - Compare both month from (1) and input month are same.{
$match: {
$expr: {
$eq: [
{
"$month": "$createdAt"
},
thisMonth.getMonth() + 1
]
}
}
}