A  relational  operator  tests  the  relationship  between   two
  ordinal,  real,  DOUBLE,  or QUADRUPLE expressions and returns a
  Boolean value.  If the relationship holds, the result  is  TRUE;
  otherwise  the  result is FALSE.  You can also apply some of the
  relational operators to string operands and to set operators.

  Relational Operators:

     operator  |  example  |  result
     --------------------------------------------
        <>         A <> B     TRUE if A is not equal to B
        <          A < B      TRUE if A is less than B
        <=         A <= B     TRUE if A is less than or equal to B
        >          A > B      TRUE if A is greater than B
        >=         A >= B     TRUE if A is greater than or equal to B