This version of the documentation is archived and no longer supported. To
upgrade your 5.0 deployment, see the MongoDB 6.0 upgrade procedures.
$returnKeyNote
Deprecated since v3.2
Starting in v3.2, the
$returnKeyoperator is deprecated inmongosh. Inmongosh, usecursor.returnKey()instead.Only return the index field or fields for the results of the query. If
$returnKeyis set totrueand the query does not use an index to perform the read operation, the returned documents will not contain any fields. Use one of the following forms:db.collection.find( { <query> } )._addSpecial( "$returnKey", true ) db.collection.find( { $query: { <query> }, $returnKey: true } )