go - How to perform subquery with MongoDB

Question

I have the following script which is valid Aggregation statement with a subquery for $nin clause. I found it's hard to do it with Go mongo driver without first performing the sub query db.ble2.distinct("_id") from Go code, how to do it at once with go driver?

db.ble.aggregate([
    { "$match": {
        "_id": { 
            "$nin": db.ble2.distinct("_id")
        }
    }},
    {"$limit": 20}
])

Answer 1

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