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Databases Mongo Basics Understanding MongoDB Data In Mongo, By Example

Henry Lin
Henry Lin
11,636 Points
Posted by Henry Lin
Henry Lin
11,636 Points

How to access a result field that stored in a variable?

I have a query like this:

var a = db.reviews.aggregate([

    {
        $unwind:"$Reviews"
    },

    {
        $match: {"HotelInfo.Name": "Desert Rose Resort"}
    },

    {

        $group:
        {
            _id:"$HotelInfo.Name",
            avg: {$avg: "$Reviews.Ratings.Overall"}
        }
    }
])

And it returned me:

{
  "result": [
    {
      "_id": "Desert Rose Resort",
      "avg": 4.522628226617499
    }
  ],
  "ok": 1
}

I want to access the "avg" field in Var a.. I am pretty sure it should looks like something like a[0].avg this.. but It did not work.. Anyone knows this?

1 Answer

Greg Kaleka
Greg Kaleka
39,021 Points
Greg Kaleka
Greg Kaleka
39,021 Points

Hi Henry,

You're very close! You just need to use the result key before you subscript into its value, a list (which you're doing correctly).

So instead of a[0].avg, you need a.result[0].avg. Let me know if you don't understand why!

Cheers :beers:

-Greg