fn:compare

fn:compare(
    $comparand1 as xs:string?, 
    $comparand2 as xs:string?
) as xs:integer?

fn:compare(
    $comparand1 as xs:string?, 
    $comparand2 as xs:string?, 
    $collation as xs:string
) as xs:integer?

The two-argument form of this function is deterministic, context-dependent, and focus-independent. It depends on collations.

The three-argument form of this function is deterministic, context-dependent, and focus-independent. It depends on collations, and static base URI.

Returns -1, 0, or 1, depending on whether the value of the $comparand1 is respectively less than, equal to, or greater than the value of $comparand2, according to the rules of the collation that is used.

The collation used by this function is determined according to the rules in Choosing a collation.

If either $comparand1 or $comparand2 is the empty sequence, the function returns the empty sequence.

This function, called with the first signature, defines the semantics of the "eq", "ne", "gt", "lt", "le" and "ge" operators on xs:string values.

The expression fn:compare('abc', 'abc') returns 0.

The expression fn:compare('Strasse', 'Straße') returns 0. (Assuming the default collation includes provisions that equate ss and the (German) character ß (sharp-s). Otherwise, the returned value depends on the semantics of the default collation.)

The expression fn:compare('Strasse', 'Straße', 'http://www.w3.org/2013/collation/UCA?lang=de;strength=primary') returns 0. (The specified collation equates ss and the (German) character ß (sharp-s).)

The expression fn:compare('Strassen', 'Straße') returns 1. (Assuming the default collation includes provisions that treat differences between ss and the (German) character ß (sharp-s) with less strength than the differences between the base characters, such as the final n. ).