List<MappingField> efs = _en(en).getMappingFields();
int old = sb.length();
for (MappingField ef : efs) {
if (fm.match(ef.getName()))
sb.append(ef.getColumnName()).append(',');
}
if (sb.length() == old)
throw Lang.makeThrow("No columns be queryed: '%s'", _en(en));