This book contains a series of illustrative examples that are labeled Useful Function. What sets them apart from regular examples is that they are likely to be directly useful in your own queries. They range from string functions like substring-after-last and replace-first to functions that modify elements and attributes, such as add-attribute.

The useful functions included in this book are part of a large library of XQuery functions called the FunctX XQuery Library, which is available at http://www.xqueryfunctions.com. This library contains a wide variety of reusable XQuery functions that can be searched or browsed by category. It also includes detailed descriptions and example function calls.