### Subtracting ` xs:dateTime ` Values The final date/time functions in this chapter involve subtracting ` xs:dateTime ` values. We saw earlier that there are various operators that take care of subtraction for the date/time types, but with these functions you can specify if you want the result as an ` xdt:yearMonthDuration ` value or an ` xdt:dayTimeDuration ` value: -
` fn:subtract-dateTimes-yielding-yearMonthDuration ` returns the difference between two ` xs:dateTime ` values as an ` xdt:yearMonthDuration ` value. -
` fn:subtract-dateTimes-yielding-dayTimeDuration ` returns the difference between two ` xs:dateTime ` values as an ` xdt:dayTimeDuration ` value. #### The ` fn:subtract-dateTimes-yielding-yearMonthDuration ` Function As you can gather from its name , this function returns an ` xdt:yearMonthDuration ` value when you subtract two ` xs:dateTime ` values. Here's how you use it: fn:subtract-dateTimes-yielding-yearMonthDuration( $srcval1 as xs:dateTime, $srcval2 as xs:dateTime) as xdt:yearMonthDuration The return value is an ` xdt:yearMonthDuration ` value containing the difference between ` $srcval1 ` and ` $srcval2 ` . For example, this expression returns an ` xdt:yearMonthDuration ` value holding the value 11 months: fn:subtract-dateTimes-yielding-yearMonthDuration(xs:dateTime("2004-01-30T19:48:00"), xs:dateTime("2003-02-28T12:00:00")) #### The ` fn:subtract-dateTimes-yielding-dayTimeDuration ` Function This function returns the difference between two ` xs:dateTime ` values as an ` xdt:dayTimeDuration ` value: fn:subtract-dateTimes-yielding-dayTimeDuration($srcval1 as xs:dateTime, $srcval2 as xs:dateTime) as xdt:dayTimeDuration The return value is an ` xdt:dayTimeDuration ` value that contains the difference between ` $srcval1 ` and ` $srcval2 ` as an ` xdt:dayTimeDuration ` value. For example, this expression returns an ` xdt:dayTimeDuration ` value corresponding to 1 day, 3 hours, 22 minutes, and 2 seconds: fn:subtract-dateTimes-yielding-dayTimeDuration(xs:dateTime("2004-04-09T04:22:07"), xs:dateTime("2004-04-08T01:00:05")) |