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$dateSubtract

Subtracts a specified time unit from a date. It's useful for calculating past dates or intervals in aggregation pipelines.

Syntax

$dateSubtract: { startDate: <dateExpression>, unit: <unit>, amount: <number>, timezone: <timezone> }

Parameters

startDateobjectrequired

The date expression to subtract from.

unitstringrequired

The time unit to subtract (for example, "day", "hour").

amountnumberrequired

The amount of the time unit to subtract.

timezonestring

Optional. Timezone for date calculation.

Examples

Subtract seven days

This query calculates the date one week before the lastUpdated field. This query uses $dateSubtract to calculate the date exactly seven days before the storeOpeningDate timestamp.

Query:

db.stores.aggregate([
  {
    $match: { _id: "e6410bb3-843d-4fa6-8c70-7472925f6d0a" }
  },
  {
    $project: {
      _id: 0,
      dateOneWeekAgo: {
        $dateSubtract: {
          startDate: "$storeOpeningDate",
          unit: "day",
          amount: 7
        }
      }
    }
  }
])

Output:

[
  {
    "dateOneWeekAgo": "2024-08-29T11:50:06.549Z"
  }
]

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