I am trying to convert Mongo Aggregation query into Java and I am kind of stuck on the second $project statement
db.ValidationResults.aggregate([ { $match: { "_id.settlementInstanceId" : "715e66c7-92ff-4619-9324-2c708489fe27", "Versions.scope" : "INPUT_QUALITY" } }, { $project: { Versions: 1, MaxVersion: { $max: "$Versions.version" } } }, { $project: { Versions: { $filter: { input: "$Versions", as: "x", cond: { $eq: [ "$$x.version", "$MaxVersion" ] } } } } }, { $unwind: "$Versions" } ]) Any help is really appreciated. TIA
Java Code -
AggregationOutput agg1 = db.getCollection("ValidationResults").aggregate( new BasicDBObject().append("$match", new BasicDBObject().append("_id.settlementInstanceId", "715e66c7-92ff-4619-9324-2c708489fe27").append("Versions.scope","INPUT_QUALITY")), new BasicDBObject().append( "$project", new BasicDBObject().append("Versions", 1).append("MaxVersion", new BasicDBObject().append("$max", "$Versions.version"))), new BasicDBObject().append( "$project", new BasicDBObject().append("Versions",new BasicDBObject().append("$filter", new BasicDBObject().append("input", "$Versions").append("cond", new BasicDBObject().append("$eq", new BasicDBObject().append("$$x.version", "$MaxVersion")))))), new BasicDBObject().append("$unwind", "$Versions") ); I am getting error on "$$x.version" such as - Unrecognized expression '$$x.version'. The full response is { "ok" : 0.0, "errmsg" : "Unrecognized expression '$$x.version'", "code" : 168, "codeName" : "InvalidPipelineOperator" }