XQuery

Appendix A. Built-in Function Reference

This appendix describes the functions that are built into XQuery. Table A-1 lists all of the built-in functions by subject for easy reference. They are all in the XPath Functions Namespace, http://www.w3.org/2005/xpath-functions.

In addition to a brief sentence explaining the purpose of the function, each function is described by the following characteristics:

• "Signature" lists the parameters and their types, and the return type of the function.

• "Usage Notes" covers the function in more detail.

• "Special Cases" lists error conditions and other unusual situations.

• "Example(s)" provides one or more example function calls with their return values.

• "Related Functions" lists names of related functions.

Important

XSLT 2.0 has some additional built-in functions, namely current, current-group, current-grouping-key, document, element-available, format-date, format-dateTime, format-number, format-time, function-available, generate-id, key, regex-group, system-property, type-available, unparsed-entity-uri, unparsed-entity-public-id, unparsed-text, unparsed-text-available. These functions are part of XSLT 2.0 only, not XQuery 1.0 and XPath 2.0, and are therefore not covered in this appendix.

Many of the built-in functions have more than one signature. For example, adjust-date-to-timezone has a signature with just $arg, and another with two arguments—$arg and $timezone:

adjust-date-to-timezone($arg as xs:date?) as xs:date? adjust-date-to-timezone($arg as xs:date?, ...