XQuery

Chapter 19. Working with Dates, Times, and Durations

XQuery provides advanced capabilities for querying, creating, and manipulating date-related values. There are eleven 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 2006, 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

Three types represent specific dates and/or times: xs:date, xs:time, and xs:dateTime. These XML Schema built-in types are based on the ISO 8601 standard. They are summarized in Table 19-1.

Table 19-1. Summary of date and time types

Type name	Description	Format	Examples
xs:date	Date	YYYY-MM-DD	2006-05-03
xs:dateTime	Date and time	YYYY-MM-DDThh:mm:ss.sss	2006-05-03T10:32:15 2006-05-03T10:32:15.55
xs:time	Time	hh:mm:ss.sss	10:32:15

The xs:date type has year, month, and day components, while xs:time has hour, minute, and seconds components. The xs:dateTime type is a concatenation of the xs:date and xs:time types, with the letter T in between them. Times (in both the xs:time and xs:dateTime types) are based on a 24-hour time period, so hours are represented as 00 through 23 (midnight ...