Is it possible to cast in a MongoDB-Query?

Question

When I have two MongoDB documents like this...

db.test.insert( {"value" : "10123"} );
db.test.insert( {"value" : "160"} );

The result of a query like:

db.test.find({"value" :{$gt : "12"} });

is..

{ "_id" : ObjectId("4c6d1b92304326161b678b89"), "value" : "160" }

It's obvious, that a string comparison is made, so that my first value is not returned. Is there any way to cast within the query?

Something like:

db.test.find({ (int) "value" :{$gt : 12} });

would be great. A query like

db.test.find({"value" :{$gt : 12} }); // without the quotes around "12"

returns nothing.

Answer 1

$gt wasn't set for this use case. You would have to use regex for strings. Probably easier to just create a new field with the number as a number.

Answer 2

You can use the following JavaScript expression:

db.test.find("this.value > 12")

This uses JavaScript's automatic conversion from string to number.