The subsequence function is used to get the sequence containing requested items present in a given sequence.
subsequence($seq as item()*, $startingLoc as xs:double, $length as xs:double)
$seq − provided sequence. Sequence can contain 0 or more items.
$startingLoc − index of items from which sub-sequence is to be created. Index starts from 1.
$length − length of subsequence.
let $items := (1,2,3,4,5,6) let $sub-items := subsequence($items,2,4) return <result> <items> { for $item in $sub-items return <item>{$item}</item> } </items> </result>
<result> <items> <item>2</item> <item>3</item> <item>4</item> <item>5</item> </items> </result>
In order to test the above-mentioned functionality, replace the contents of books.xqy (mentioned in Environment Setup chapter) with the above XQuery expression and execute the XQueryTester java program to verify the result.