¿Cómo usar la función sql nativa con la consulta HQL?

En Attachment dominio añadir nuevo campo Long fileBytesLength y dentro del cierre del mapeo agregue la fórmula para calcular la longitud de fileBytes campo.

class Attachment {

    String createUserName
    String originalFilename

    byte[] fileBytes
    Long fileBytesLength

    Date dateCreated
    //Other Properties

    static mapping = {
        //Other mappings
        fileLength formula: "dbms_lob.getlength(fileBytes)"
    }
}

Y luego modifique la consulta a:

def results = Attachment.executeQuery(
    'select id, originalFilename, fileBytesLength, dateCreated, createUserName '+
    'from Attachment a where a.id not in '+
         '(select attachmentId from SpecVersion sv where sv.attachmentId is not null) '+
    'and a.dateCreated > sysdate - 30')