1 XMLGROUP (
2+ ,
2 expression 
2.1? AS qname-identifier
3? 
3 ORDER BY
3.1+ ,
3.1 sort-key-expression
3.1.1! ASC
3.1.1?
3.1.1 DESC
4? OPTION
4.1+ 
4.1.0! ROW "row"
4.1.0! ROW row-name
4.1! ROOT "rowset"
4.1! ROOT root-name
4.1 AS ATTRIBUTES
4.2

4.3 )