oracle分页查询(查询第六到第十条数据)，分步解析    1，select * from emp;    2，select a1.*,rownum rn from ((select * from emp) a1);    3，select a1.*,rownum rn from ((select * from emp) a1) where rownum<=10;    4，select * from (select a1.*,rownum rn from ((select * from emp) a1) where rownum<=10) where rn>=6;         SQL> select * from (select a1.*,rownum rn from ((select * from emp) a1) where rownum<=10) where rn>=6;     EMPNO ENAME      JOB         MGR HIREDATE          SAL      COMM DEPTNO         RN  ----- ---------- --------- ----- ----------- --------- --------- ------ ----------   7698 BLAKE      MANAGER    7839 1981-5-1      2850.00               30          6   7782 CLARK      MANAGER    7839 1981-6-9      2450.00               10          7   7788 SCOTT      ANALYST    7566 1987-4-19     3000.00               20          8   7839 KING       PRESIDENT       1981-11-17    5000.00               10          9   7844 TURNER     SALESMAN   7698 1981-9-8      1500.00      0.00     30         10