elemMatch Query with $gt and $lt

Question

I'm trying to implement an elemMatch query with $gt and $lt in Casbah.

"Testing $gt and $lt in $elemMatch" should "return results" in { 

val TEST = "test"

val db = MongoClient()(TEST)
val collection = db(TEST)

val obj: JsValue = Json.parse("""{ "records" : [{"n" : "Name", "age": 5}]}""")
val doc: DBObject = JSON.parse(obj.toString).asInstanceOf[DBObject]

collection.insert(doc)

val elemMatch = "records" $elemMatch (MongoDBObject("n" -> "Name", "age" $gt 0))
val results = collection.find(elemMatch, MongoDBObject("_id" -> 1))

On the val elemMatch line, I'm seeing this compile-time error:

[error] ...\TestElemMatch.scala:51: ')' expected but integer
 literal found.
[error]         val elemMatch = "records" $elemMatch (MongoDBObject("n" -> "Name", "age" -> $gt 0))
                                                                                   ^

http://docs.mongodb.org/manual/reference/operator/query/elemMatch/

Answer 1

the way the operator $gt is used is incorrect, this should work

val elemMatch = MongoDBObject("records" -> MongoDBObject("$elemMatch" -> MongoDBObject("n" -> "Name", "age"->MongoDBObject( "$gt"-> 0))))