Converts all the lowercase characters of $string-var to their uppercase form.
If the value of $string-var is the empty sequence, the empty sequence is returned. The empty sequence is a sequence containing zero items (), which is similar to null in SQL.
xf:upper-case(xs:string? $string-var) —> xs:string?
Returns the $string-var source string converted to uppercase characters.
Invoking upper-case("cat") returns the string CAT as shown in the following example query:
<result>{xf:upper-case("cat")}</result>
The preceding query generates the following result:
<result>CAT</result>
Invoking upper-case(()) returns the null string as shown in the following example query:
<result>{xf:upper-case(())}</result>
Note: The string: () is the empty sequence (similar to a SQL null) which is a sequence containing zero items.
The preceding query generates the following result:
<result/>
W3C upper-case function description.