CODEWITHSUNDEEP
mongodbaggregation-frameworkpymongo
nishant kumar
nishant kumar

Reputation: 517

mongodb return number of matched expression

I have many document in collection I want to run a aggregation query. Let say sample doc are like as shown below

{"A":1,"B":2, "c":"x"}
{"A":3,"B":2, "c":"play"}
{"A":1,"B":2, "c":"test"}

to these doc I want to run a OR query and also I want to return number of or condition matched. for example if query is

{"A":1, "A":3, "c":"test"}

it should return result like

[
    {"A":1,"B":2, "c":"x", "count":1}
    {"A":3,"B":2, "c":"play", "count", 1}
    {"A":1,"B":2, "c":"test", "count":2}
]

Upvotes: 0

Views: 48

Answers (1)

mickl
mickl

Reputation: 49945

You can use $addFields and evaluate your value based on specified conditions:

db.col.aggregate([
    {
        $addFields: {
            count: {
                $add: [
                    { $cond: [ { $eq: ["$A", 1] }, 1, 0 ] },
                    { $cond: [ { $eq: ["$A", 3] }, 1, 0 ] },
                    { $cond: [ { $eq: ["$c", "test"] }, 1, 0 ] },
                ]
            }
        }
    },
    {
        $match: {
            "count": { $gt: 0 }
        }
    }
])

Upvotes: 1

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