XQuery Functions

XQuery provides a rich set of built-in functions that can be used to manipulate and process XML data. These functions are part of the XQuery standard library and are available for use in XQuery expressions. Here are some of the commonly used XQuery functions:

1. String Functions:

• fn:string() – Converts any data type to a string.
• fn:string-length() – Calculates the length of a string.
• fn:substring() – Extracts a substring from a given string.
• fn:concat() – Concatenates multiple strings into a single string.
• fn:contains() – Checks if a string contains a specified substring.
• fn:starts-with() – Checks if a string starts with a specified prefix.
• fn:ends-with() – Checks if a string ends with a specified suffix.
• fn:replace() – Replaces occurrences of a regular expression pattern in a string.

1. Numeric Functions:

• fn:sum() – Calculates the sum of numeric values in a sequence.
• fn:avg() – Calculates the average of numeric values in a sequence.
• fn:max() – Finds the maximum value in a sequence.
• fn:min() – Finds the minimum value in a sequence.
• fn:round() – Rounds a numeric value to the nearest integer.
• fn:floor() – Rounds down a numeric value to the nearest integer.
• fn:ceiling() – Rounds up a numeric value to the nearest integer.

1. Boolean Functions:

• fn:boolean() – Converts any data type to a boolean value.
• fn:not() – Negates a boolean value.
• fn:empty() – Checks if a sequence is empty.
• fn:exists() – Checks if a node or sequence exists.

1. Date and Time Functions:

• fn:current-dateTime() – Retrieves the current date and time.
• fn:current-date() – Retrieves the current date.
• fn:current-time() – Retrieves the current time.
• fn:year-from-dateTime(), fn:month-from-dateTime(), fn:day-from-dateTime(), etc. – Extracts components from date/time values.

1. Sequence Functions:

• fn:count() – Counts the number of items in a sequence.
• fn:first() – Returns the first item in a sequence.
• fn:last() – Returns the last item in a sequence.

1. Node Functions:

• fn:name() – Retrieves the name of an element or attribute node.
• fn:local-name() – Retrieves the local name of an element or attribute node.
• fn:namespace-uri() – Retrieves the namespace URI of an element or attribute node.

1. Type Conversion Functions:

• fn:xs:integer(), fn:xs:double(), fn:xs:string(), etc. – Convert values to specific XML Schema types.

These are just some of the XQuery functions available for working with XML data. XQuery is a powerful language with a wide range of functions that enable you to perform various operations on XML documents efficiently. To learn more about XQuery functions and their usage, refer to the XQuery documentation or tutorials available online.