The ALL expression is used with a subquery, and is true if all the values returned by the subquery are true, or if the subquery is empty.
The ANY expression is used with a subquery, and is true if some of the values returned by the subquery are true. An ANY expression is false if the subquery result is empty, or if all the values returned are false. The SOME keyword is synonymous with ANY.
The ALL and ANY expressions are used with the =, <, <=, >, >=, <> comparison operators.
The following example finds all employees whose salary is higher than the salary of the managers in the employee’s department:
SELECT emp FROM Employee emp WHERE emp.salary > ALL ( SELECT m.salary FROM Manager m WHERE m.department = emp.department)