Tamino XQuery User Guide - Software AG Documentation

Query Examples
Explanation
Again, a FLWOR expression is used in the query, but this time there is an additional where clause:
where $b/@year > 1994
It restricts the bindings to the variable $b to those that meet the condition in the expression following
the keyword where: Only those book elements are retained that have an attribute year whose numerical
value is greater than 1994. So it has the same effect as the WHERE clause in SQL.
return
{ $b/@year }
{ $b/title }
An element constructor is used that creates a new element book which is then filled by two enclosed
expressions: the first one evaluates to an attribute that is attached to the element book, the second
expression is used as before.
You could also introduce an additional variable that is bound to the attribute year by using the
let clause. The query then reads:
for $b in input()/bib/book
let $y := $b/@year
where $y > 1994
return
{ $y }
{ $b/title }
The let clause adds an additional binding so that you can refer to $y instead of referring to
$b/@year.
See FLWORExpr in the language reference for details.
Note: Although a sequence of book elements is not a well-formed XML element by itself,
the resulting node sequence is serialized by Tamino into an xq:result node, which is in
itself a new well-formed XML document.
XQuery User Guide
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