$isoDayOfWeek (aggregation)
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Definition
$isoDayOfWeek
New in version 3.4.
Returns the weekday number in ISO 8601 format, ranging from
1
(for Monday) to7
(for Sunday).The
$isoDayOfWeek
expression has the following operator expression syntax:{ $isoDayOfWeek: <dateExpression> } The argument can be:
An expression that resolves to a Date, a Timestamp, or an ObjectID.
A document with this format:
{ date: <dateExpression>, timezone: <tzExpression> } FieldDescriptiondate
The date to which the operator is applied.<dateExpression>
must be a valid expression that resolves to a Date, a Timestamp, or an ObjectID.timezone
Optional.
The timezone of the operation result.<tzExpression>
must be a valid expression that resolves to a string formatted as either an Olson Timezone Identifier or a UTC Offset. If notimezone
is provided, the result is displayed inUTC
.Note
Etc/ Timezones
Etc/*
timezones are supported starting in MongoDB 5.0.4. In earlier versions of MongoDB, use alternative timezone designations. For example, useUTC
instead ofEtc/UTC
.FormatExamplesOlson Timezone Identifier
"America/New_York" "Europe/London" "GMT" UTC Offset
+/-[hh]:[mm], e.g. "+04:45" +/-[hh][mm], e.g. "-0530" +/-[hh], e.g. "+03"
Behavior
Example | Result | ||||
---|---|---|---|---|---|
| 5 | ||||
| 2 | ||||
| 7 | ||||
| 6 | ||||
| 5 | ||||
| error | ||||
| error | ||||
| error |
Note
$isoDayOfWeek cannot take a string as an argument.
Example
A collection called birthdays
contains the following documents:
{ "_id" : 1, "name" : "Betty", "birthday" : ISODate("1993-09-21T00:00:00Z") } { "_id" : 2, "name" : "Veronica", "birthday" : ISODate("1981-11-07T00:00:00Z") }
The following operation returns the weekday number for each
birthday
field.
db.dates.aggregate( [ { $project: { _id: 0, name: "$name", dayOfWeek: { $isoDayOfWeek: "$birthday" } } } ] )
The operation returns the following results:
{ "name" : "Betty", "dayOfWeek" : 2 } { "name" : "Veronica", "dayOfWeek" : 6 }