How to hide _id from Aggregation?

Question

I\'ve this query:

produits = yield motor.Op(db.users.aggregate, [{\"$unwind\":\"$pup\"},{\"$match\":{\"pup.spec.np\":nomp}}, {\"$group\":{\"_id\":\"$pup.spec         


        

Answer 1

From mongodb docs

You can $project the results to exclude the _id - is this what you mean?

http://docs.mongodb.org/manual/reference/aggregation/#pipeline

Note The _id field is always included by default. You may explicitly exclude _id as follows:

db.article.aggregate(
    { $project : {
        _id : 0 ,
        title : 1 ,
        author : 1
    }}
);

From you're example, the first operation in the pipeline would be to exclude the _id and include the other attribs.