Tamino XQuery User Guide - Software AG Documentation

Query Examples
Explanation
Building upon the FLWOR expression from the last example, we modified the return clause:
return
{ string($y) }
{ $b/title }
The year of publication is now the contents of the new element year. As the expression $b/@year
represents an attribute node, we need to turn its value into a string by applying the function
string().
sort by (title)
All book elements are sorted by their child element title in ascending order. The FLWOR expression
evaluates to a sequence of items and determines the context node for sort by (XQuery calls
this evaluation context inner focus). These input items are then reordered according to the sort
criterion and returned as a sequence of output items. As book is the context node for each input
item, the result is a sequence of book elements sorted alphabetically by title in the default order,
which is ascending.
An alternative version of this query is:
for $b in input()/bib/book
let $y := $b/@year
where $y > 1991
return
{ string($y) }
{ $b/title }
sort by (title)
Putting the sort at the end of the for clause has the advantage that the data type of title is retained
and the query can be optimized, while newly constructed nodes have no type information.
See SortExpr and fn:string in the language reference for details.
XQuery User Guide
13