$dateAdd

  • Article

The $dateAdd operator adds a specified number of time units to a date. It's useful in scenarios where you need to calculate future dates based on a given date and a time interval.

Syntax

$dateAdd: {
   startDate: <expression>,
   unit: <string>,
   amount: <number>,
   timezone: <string>  // Optional
}

Parameters

Description
startDate The starting date for the addition operation.
unit The unit of time to add. Valid units include: year, quarter, month, week, day, hour, minute, second, millisecond.
amount The number of units to add.
timezone Optional. The timezone to use for the operation.

Examples

Example 1: Adding days to a date

db.collection.aggregate([
   {
      $project: {
         eventName: 1,
         newEndDate: {
            $dateAdd: {
               startDate: {
                  $dateFromParts: {
                     year: "$promotionEvents.promotionalDates.endDate.Year",
                     month: "$promotionEvents.promotionalDates.endDate.Month",
                     day: "$promotionEvents.promotionalDates.endDate.Day"
                  }
               },
               unit: "day",
               amount: 7
            }
         }
      }
   }
])

Example 2: Adding months to a date

db.collection.aggregate([
   {
      $project: {
         eventName: 1,
         newStartDate: {
            $dateAdd: {
               startDate: {
                  $dateFromParts: {
                     year: "$promotionEvents.promotionalDates.startDate.Year",
                     month: "$promotionEvents.promotionalDates.startDate.Month",
                     day: "$promotionEvents.promotionalDates.startDate.Day"
                  }
               },
               unit: "month",
               amount: 1
            }
         }
      }
   }
])

Related content