XQuery, 2nd Edition

Chapter 20. Working with Dates, Times, and Durations

XQuery provides advanced capabilities for querying, creating, and manipulating date-related values. There are twelve date-related types built into XQuery. They fall into three categories:

• The date and time types, which represent a point in time—for example, a specific date or time

• The duration types, which represent periods of time, such as a number of years or minutes

• The date component types, which represent parts of dates, such as the year 2015, the month of May, or the 10th day of each month

This chapter explains the date-related types used in XQuery and the functions and operators that act on them.

The Date and Time Types

Four types represent specific dates and/or times: xs:date, xs:time, xs:dateTime, and xs:dateTimeStamp. These XML Schema built-in types are based on the ISO 8601 standard. They are summarized in Table 20-1.

Table 20-1. Summary of date and time types

Type name	Description	Format (without time zone)	Examples
xs:date	Date	YYYY-MM-DD	2015-05-03
xs:time	Time	hh:mm:ss.sss	10:32:15
xs:dateTime	Date and time with optional time zone	YYYY-MM-DDThh:mm:ss.sss	2015-05-03T10:32:15, 2015-05-03T10:32:15.55
xs:dateTimeStamp	Date and time with mandatory time zone	YYYY-MM-DDThh:mm:ss.sss	2015-05-03T10:32:15-05:00, 2015-05-03T10:32:15.55Z

The xs:date type has year, month, and day components, while xs:time has hour, minute, and seconds components. The format of the xs:dateTime and xs:dateTimeStamp types is a concatenation of the