CODEWITHSUNDEEP
mongodbmongodb-query
aedan
aedan

Reputation: 217

Check if all element in an array have the value for a certain field in mongodb

I need to verify that for each document it has the same value for the baz field.

The structure looks like this.

{
    _id : 111111,
    foo : 123123,
    bar : [
        {
            subId : 121212,
            baz : abc123
        },
        {
            subId : 131313,
            baz : abc123
        },
    ]
},
{
    _id : 222222,
    foo : 234234,
    bar : [
        {
            subId : 212121,
            baz : def456
        },
        {
            subId : 313131,
            baz : def456
        },
    ]
},

Basically I just need to make sure that for each document, baz should be always the same. How can I query it?

Upvotes: 0

Views: 37

Answers (1)

Dheemanth Bhat
Dheemanth Bhat

Reputation: 4452

Try This:

db.allSame.aggregate([
    {
        $addFields: {
            "uniqueBazCount": {
                $sum: {
                    $map: {
                        input: "$bar",
                        as: "item",
                        in: {
                            $cond: [{ $eq: ["$$item.baz", { $arrayElemAt: ["$bar.baz", 0] }] }, 0, 1]
                        }
                    }
                }
            }
        }
    },
    {
        $match: { uniqueBazCount: 0 }
    }
]);

To get the docs with different values change $match as below:

{
    $match: {
        uniqueBazCount: { $gt: 0 }
    }
}

Upvotes: 1

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