XOR

 The XOR function returns a  value  (of  the  same  type  as  the
 parameters)  of  a  binary logical exclusive-OR operation on two
 specified parameters.


 Syntax:

    XOR( p1,p2 )


 The 'p1' and 'p2' parameters must be of the same type  and  must
 be of either the BOOLEAN or SET types.