Read XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition Online
Authors: Michael Kay
xs:gYear xs:gYearMonth xs:gMonth xs:gMonthDay xs:gDay xs:QName xs:base64Binary xs:hexBinary xs:NOTATION | These types have no ordering defined. Using any of the operators lt , le , gt , ge with values of these types is a type error. There's no particular reason for this restriction—in most of these cases it would have been quite possible to define a useful ordering—but the working groups decided it wasn't needed. |
xs:duration | xs:duration values themselves are not considered to be ordered, so the operators lt , le , gt , and ge are not available. This removes the problem of deciding whether 30 days is less than, equal to, or greater than one month. The two XPath subtypes of xs:duration , namely xs:yearMonthDuration and xs:dayTimeDuration , are much more well behaved. The effect of comparing them is the same as converting the value to a number of months, or a number of seconds, and comparing the two numbers. This means, for example, that PT36H (36 hours) is greater than P1D (one day). |