CODEWITHSUNDEEP
node.jsmongodb
Peter
Peter

Reputation: 505

Multiple groupings in mongodb

I am creating a search form for users in my mongo database having this structure

[
    { _id: 45aba8a34a8a,
      name: blabla,
      country: france,
      region: alsace
     },
     { _id: 6ccbef3a4a83,
      name: blabla,
      country: germany,
      region: hessen
     }
]

What I am trying to achieve is to get a list of possible countries and regions in the database. I can partly achieve this by the following code

collection.aggregate([
    {
        $group: {
            _id: "$country"
        }
    }
], function (err, res) {
    ...
});

However this will only give me the grouped countries and not regions. Is there a way to do this in a single aggregation? I guess the ideal result would be something like

{
    countries: [ 'france', 'germany', ... ],
    regions: [ 'alsace', 'hessen', ...]
}

But I haven't been able to find how to obtain this anywhere on the net.

Upvotes: 0

Views: 32

Answers (1)

Lalit Agarwal
Lalit Agarwal

Reputation: 2354

You should try something like below.

collection.aggregate([
    {
        $group: {
            _id: { country: "$country", region: "$region" }
        }
    }
], function (err, res) {
    ...
});

You may look at $addToSet in case you need distinct records.

Upvotes: 1

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