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Asked: 2026-06-01T20:07:14+00:00

Mongo DB: I’m looking to make one query to return both the first and

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Mongo DB: I’m looking to make one query to return both the first and last element of an array. I realize that I can do this multiple queries, but I would really like to do it with one.

Assume a collection “test” where each objects has an array “arr” of numbers:

 db.test.find({},{arr:{$slice: -1},arr:{$slice: 1}});

This will result in the following:

 { "_id" : ObjectId("xxx"), "arr" : [ 1 ] }    <-- 1 is the first element

Is there a way to maybe alias the results? Similar to what the mysql AS keyword would allow in a query?

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1 Answer

  1. Editorial Team

    This is not possible at the moment but will be with the Aggregation Framework that’s in development now if I understand your functional requirement correctly.

    You have to wonder about your schema if you have this requirement in the first place though. Are you sure there isn’t a more elegant way to get this to work by changing your schema accordingly?

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