Oracle DB Select - Input parameters problem

I'm querying an Oracle DB with Database Connector ( Select operation ) and I want to parametrize one field.

This is the query:

"SELECT id, name, code FROM employees WHERE code = nvl( :auxCode, '1-11') order by id"

This is the input parameter:

{

'auxCode': vars.code

}

And finally, this is de variable ( named code ):

(attributes.queryParams.code as String default '')

If I send code=2-22, I'm having this error:

Message        : An SQLException was provoked by the following failure: java.lang.NumberFormatException: For input string: "2-"

Please, any idea?

Best regards!!