Why this select query to Oracle database doesn't work?

Why this select query to Oracle database doesn't work?

First I tested simple cases:
cmd.Parameters.Add(new OracleParameter(":paramCode",
OracleDbType.NVarchar2)).Value = userCode;
cmd.CommandText = "SELECT * FROM VIEWUSERDATA WHERE Codigo = :paramCode";
cmd.CommandType = System.Data.CommandType.Text;
OracleDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
//Works, retrieve data
}
Another:
cmd.Parameters.Add(new OracleParameter(":paramRole",
OracleDbType.NVarchar2)).Value = userRole;
cmd.CommandText = "SELECT * FROM VIEWUSERDATA WHERE Role = :paramRole";
...
while (reader.Read())
{
//Also works
}
But when join, doesn't work.
cmd.Parameters.Add(new OracleParameter(":paramCode",
OracleDbType.NVarchar2)).Value = userCode;
cmd.Parameters.Add(new OracleParameter(":paramRole",
OracleDbType.NVarchar2)).Value = userRole;
cmd.CommandText = "SELECT * FROM VIEWUSERDATA WHERE Role = :paramRole AND
Code = :paramCode";
...
while (reader.Read())//don't retrieve anything
{
}
Data exists, If I do the query in an external query editor(window) works
fine.
Thanks.