CODEWITHSUNDEEP
mongodbmongodb-queryaggregation-framework
Craig
Craig

Reputation: 2193

MongoDB Aggregation: Use field value of current document in $match $or query

I have an aggregation pipeline and my documents are currently in the following format :

{
    "user": "5e3d326537df7e4dda73eb23",
    "sharedWithGroups": [ "5e3d326437df7e4dda73eb13", "5e3d326437df7e4dda73eb19" ],
    "userGroupIds": [ "5e3d326437df7e4dda73eb19" ]
}

Where userGroupIds is the result of a previous stage, where I find the IDs of the groups that the user is in.

I'm trying to add a match stage to the pipeline to find all documents which have either a user ID that matches a specific ID, OR have a sharedWithGroups property that contains one of the entries in userGroupIds.

I thought that something like this would work :

{
  $match: {
    $or: [
      { user: "5e3d326537df7e4dda73eb23" },
      { sharedWithGroups: { $in: "$userGroupIds" } }
    ]
  }
}

But I get an error: $in needs an array. I don't understand because $userGroupIds is definitely an array. I've tried using $expr, thinking that the field value may not be resolving, but have had no luck. Is this approach possible, or is there another/better way to filter these documents using multiple criteria?

Upvotes: 2

Views: 1380

Answers (1)

whoami - fakeFaceTrueSoul
whoami - fakeFaceTrueSoul

Reputation: 17935

You can try this :

{
    $match: {
        $or: [
            { user: "5e3d326537df7e4dda73eb23" },
            { $expr: { $gt: [{ $size: { $setIntersection: ["$sharedWithGroups", "$userGroupIds"] } }, 0] } }
        ]
    }
}

Test : MongoDB-Playground

(Or)

{
    $match: {
        $or: [
            { user: "5e3d326537df7e4dda73eb23" },
            { $expr: { $setIsSubset: ["$userGroupIds", "$sharedWithGroups"] } }
        ]
    }
}

Test : MongoDB-Playground

Upvotes: 3

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