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$toDecimal

The `$toDecimal` operator converts an input expression into a Decimal value. Long, Double or Int values are simply converted to a Decimal data type, while Decimal values are returned as is. A boolean value of true is converted to 1, while a boolean false is converted to 0. Lastly, ISODates are converted to a Decimal value corresponding to the number of milliseconds since January 1st, 1970 represented by the ISODate value.

Syntax

{
  $toDecimal: <expression>
}

Parameters

expressionobjectrequired

The specified value to convert into a Decimal value.

Examples

Sample Data

{
  "_id": "0fcc0bf0-ed18-4ab8-b558-9848e18058f4",
  "name": "First Up Consultants | Beverage Shop",
  "location": { "lat": -89.2384 }
}

Convert a Double to Decimal

Convert latitude field from double to decimal value.

This query converts a double to a Decimal128 value.

Query:

db.stores.aggregate([{
  $match: { _id: "b0107631-9370-4acd-aafa-8ac3511e623d" }
}, {
  $project: {
    originalLatitude: "$location.lat",
    latitudeAsDecimal: { $toDecimal: "$location.lat" }
  }
}])

Output:

[
  {
    "_id": "b0107631-9370-4acd-aafa-8ac3511e623d",
    "originalLatitude": 72.8377,
    "latitudeAsDecimal": "Decimal128('72.8377000000000')"
  }
]

Convert an ISODate to Decimal

Convert an ISO date to decimal milliseconds.

This query converts a date to milliseconds since epoch.

Query:

db.stores.aggregate([{
  $match: { _id: "b0107631-9370-4acd-aafa-8ac3511e623d" }
}, {
  $project: {
    dateAsDecimal: {
      $toDecimal: ISODate("2025-01-06T00:00:00.000Z")
    }
  }
}])

Output:

[
  {
    "_id": "b0107631-9370-4acd-aafa-8ac3511e623d",
    "dateAsDecimal": "Decimal128('1736121600000')"
  }
]

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