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  1. Documentation
  2. DOCS-10404

Docs for SERVER-9406: Allow treating ObjectId type as date in $project phase

    • Type: Icon: Task Task
    • Resolution: Fixed
    • Priority: Icon: Major - P3 Major - P3
    • 3.5.9
    • Affects Version/s: None
    • Component/s: None
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      Documentation Request Summary:

      Aggregation date expressions will accept input of type ObjectId.

      Engineering Ticket Description:

      Since ObjectId() encompasses an approximation of insertion date it would be helpful if _id/things of ObjectId() type could be operated/projected the same way as Datetime type object.

      {$project:{$year:"$_id"}} would extract year out of ObjectId().getTimestamp equivalent.{case}

      One question would be whether ObjectId could be operated on directly via date/interval arithmetic. I.e. whether it can be used anywhere a date can be used returning a standard Datetime type as a result from say {$subtract:["$_id",86400000]} which can only return ts of one day before that ObjectId's timestamp.

            kevin.albertson@mongodb.com Kevin Albertson
            emily.hall Emily Hall
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              6 years, 23 weeks, 2 days ago