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  1. Core Server
  2. SERVER-9023

$add returns null if any of the operands are null

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    • Type: Icon: Bug Bug
    • Resolution: Done
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 2.4.0
    • Component/s: Aggregation Framework
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    • Environment:
      MongoDB 2.4.0, Mac OS X 10.8.2
    • ALL
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      > db.things.insert({a:2,b:3})
> db.things.aggregate({$project:{total:{$add:["$a","$b"]}}})
{
	"result" : [
		{
			"_id" : ObjectId("5148c8d7d2f22a5f45c45d64"),
			"total" : 5
		}
	],
	"ok" : 1
}
> db.things.aggregate({$project:{total:{$add:["$a","$b","$c"]}}})
{
	"result" : [
		{
			"_id" : ObjectId("5148c8d7d2f22a5f45c45d64"),
			"total" : null
		}
	],
	"ok" : 1
}
      Show
      > db.things.insert({a:2,b:3}) > db.things.aggregate({$project:{total:{$add:[ "$a" , "$b" ]}}}) { "result" : [ { "_id" : ObjectId( "5148c8d7d2f22a5f45c45d64" ), "total" : 5 } ], "ok" : 1 } > db.things.aggregate({$project:{total:{$add:[ "$a" , "$b" , "$c" ]}}}) { "result" : [ { "_id" : ObjectId( "5148c8d7d2f22a5f45c45d64" ), "total" : null } ], "ok" : 1 }
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      In version 2.2, the aggregation framework $add operator correctly added all non-null operands. In version 2.4, if any one of the operands is null, it returns null.

            Assignee:
            Unassigned Unassigned
            Reporter:
            tdahlke Travis Dahlke
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            Watchers:
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              Created:
              Updated:
              Resolved: