Hello, the support for XQuery 3.0 is really wonderful! Thank you. Just a trifle: I think there is a little bug concerning the "group by" clause and the case that a non-grouping variable is reused as grouping variable, but the shorthand notation for this is not used. According to the spec, these expressions should be equivalent: group by $x group by $x := $x I observed that in the shorthand notation $x references the grouping variable, that is, one value per group, as it should. But in the longhand notation, $x references the variable in the pre-grouping variable, and I suppose this should not be so. For a full example, see below. Kind regards, Hans-Juergen PS: Full example: Code: for $x in (1, 1, 2) group by $x := $x return <r x="{$x}"/> Output: <r x="1 1"/> <r x="2"/>