set-expression-1 DIFF set-expression-2

The DIFF operator returns a set that contains the set difference of the left and right operands. The result set contains values that are members of the left operand but not members of the right operand. The operands must have compatible set types. The following statements evaluate and print a set difference:

   proc optmodel;
      put ({1,3} diff {2,3}); /* outputs {1} */