The primitive type xs:dateTime represents a combined date and time. The lexical representation of xs:dateTime is YYYY-MM-DDThh:mm:ss.sss, which is a concatenation of the xs:date and xs:time representation, with an uppercase letter T between them. The constraints described for the xs:date and xs:time types are also true for xs:dateTime. A time zone can be added to the end, as described in "Time Zones" in Chapter 19.
Table B-4 lists some values of the xs:dateTime type. For more information on working with dates and times, see Chapter 19.
Table B-4. Values of the xs:dateTime type
Values of type xs:dateTime can be constructed using the standard xs:dateTime constructor. In addition, a function named dateTime can be used to construct an xs:dateTime value from an xs:date and an xs:time. You can obtain the current date/time using the current-dateTime function, which returns a value of type xs:dateTime.
It is possible to cast some values to and from xs:dateTime, as shown in the examples in Table B-5. You can split an xs:dateTime value into its date and time components by casting it to xs:date or xs:time. Additionally, xs:date values can be cast to xs:dateTime, in which case the time components are filled in with zeros. Time zones are unchanged by the cast.