Boolean Constructor Functions - false (XQuery)
Applies to: 
SQL Server
Returns the xs:boolean value False. This is equivalent to xs:boolean("0").
Syntax
fn:false() as xs:boolean
Examples
This topic provides XQuery examples against XML instances that are stored in various xml type columns in the AdventureWorks database.
A. Using the false() XQuery Boolean function
For a working sample, see true Function (XQuery).