MINUS

Removes the members of one or more result sets from a another result set.

set1 MINUS set2

set1	A result set that resulted from the execution of a set-producing command. The sets must all have the same component structure.
set2	A result set that resulted from the execution of a set-producing command. The sets must all have the same component structure.

When used within a FIND command, the result set contains all members of set1 that are not also in set2, and so on.