示例：
SELECT ename,job,sal FROM emp WHERE sal<ANY(SELECT sal FROM emp WHERE job='SALESMAN');
ANY:结果集的一条记录在子查询中只要有一条记录大于结果集中的记录，就查询出这条记录;
类似于：SELECT ename,job,sal FROM emp WHERE sal<(SELECT max(sal) FROM emp WHERE job='SALESMAN');

ALL：SELECT ename,job,sal FROM emp WHERE sal>ALL(SELECT sal FROM emp WHERE job='SALESMAN');
与ANY相反，类似于：SELECT ename,job,sal FROM emp WHERE sal>(SELECT min(sal) FROM emp WHERE job='SALESMAN');

ROWID:伪列，表示表中每一行记录在数据文件中的物理地址。