String concatenation and bang operators

String concatenation

xquery version "3.0"; let $who := "world" return "Hello " || $who || "!"

Bang operator

Can be used instead of simple for expressions. The expression to the right of the operator is evaluated once for each item in the left-hand sequence, setting the context item to the current item.

xquery version "3.0"; ("Hello", "world") ! upper-case(.)