$week
Returns the week number for a date as a value between 0 and 53. Week 0 begins on January 1, and subsequent weeks begin on Sundays. If the date is null or missing, $week returns null.
Syntax
$week: <dateExpression>
Parameters
dateExpression
objectrequiredAny expression that resolves to a Date, Timestamp, or ObjectId.
timezone
stringOptional. The timezone to use for the calculation. Can be an Olson Timezone Identifier (for example, "America/New_York") or a UTC offset (for example, "+0530").
Examples
Get week number for store opening date
This query extracts the week number from the store opening date.
Query:
db.stores.aggregate([
{ $match: { _id: "905d1939-e03a-413e-a9c4-221f74055aac" } },
{
$project: {
name: 1,
storeOpeningDate: 1,
openingWeek: { $week: { $toDate: "$storeOpeningDate" } }
}
}
])
Output:
[
{
"_id": "905d1939-e03a-413e-a9c4-221f74055aac",
"name": "Trey Research | Home Office Depot - Lake Freeda",
"storeOpeningDate": ISODate("2024-12-30T22:55:25.779Z"),
"openingWeek": 52
}
]
Group stores by opening week
This query groups stores by the week they were opened for analysis.
Query:
db.stores.aggregate([
{
$project: {
name: 1,
openingWeek: { $week: { $toDate: "$storeOpeningDate" } },
openingYear: { $year: { $toDate: "$storeOpeningDate" } }
}
},
{
$group: {
_id: { week: "$openingWeek", year: "$openingYear" },
storeCount: { $sum: 1 },
stores: { $push: "$name" }
}
},
{ $sort: { "_id.year": 1, "_id.week": -1 } },
{ $limit : 3 } ])
Output:
[
{
"_id": { "week": 40, "year": 2021 },
"storeCount": 1,
"stores": [ "First Up Consultants | Bed and Bath Center - South Amir" ]
},
{
"_id": { "week": 52, "year": 2024 },
"storeCount": 1,
"stores": [ "Trey Research | Home Office Depot - Lake Freeda" ]
},
{
"_id": { "week": 50, "year": 2024 },
"storeCount": 2,
"stores": [
"Fourth Coffee | Paper Product Bazaar - Jordanechester",
"Adatum Corporation | Pet Supply Center - West Cassie"
]
}
]