CODEWITHSUNDEEP
arraysnode.jsmongodb
NotaMan
NotaMan

Reputation: 65

Query an array of users based on an array of users

Basically I'm having trouble understanding how I would figure this out.

I have a document in a mongodb collection, and that document has field called friends which is an array of usernames.

I want to query through each username in the array friends, and have an array of those user documents. I'm terrible at explaining maybe if I draw this out it'll make sense.

mongodb document:

{
    "_id": {
        "$oid": "59a20e65f94cb5e924af774e"
    },
    "name": "Nick",
    "friends": ["Jones","Mark","Mike"]
}

Now with this friends array, I want to search the same collection for an object with the "name" Jones, Mark, and Mike. When I find that object, I want to put it into an array.

Basically I want it to return this, (for this example let's say Jones, Mark, and Mike only have one friend, and that friend is Nick.

[{
    "_id": {
        "$oid": "59a20e65f94cb5e924af774e"
    },
    "name": "Jones",
    "friends": ["Nick"]
},
{
    "_id": {
        "$oid": "59a20e65f94cb5e924af774e"
    },
    "name": "Mark",
    "friends": ["Nick"]
},
{
    "_id": {
        "$oid": "59a20e65f94cb5e924af774e"
    },
    "name": "Mike",
    "friends": ["Nick"]
}]

^ an array of three objects, which are all the friends of Nick.

If you need any more explanation please let me know, I'm terrible at this type of stuff.

For the record, I'm using node, and basic mongodb (not mongoose).

Upvotes: 0

Views: 73

Answers (1)

Mikey
Mikey

Reputation: 6766

I believe you are looking for $in operator.

// doc.friends = ["Jones","Mark","Mike"]

db.collection.find({ name: { $in: doc.friends }})

Upvotes: 1

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