Oracle 分页

1.根据rowid来分

select * from emp

where rowid in

(select rid from

(select rownum rn, rid from

(select rowid rid, empno from emp order by empno desc)

where rownum<10)

where rn>4)

order by empno desc;

执行时间0.03秒

2.按分析函数来分

select * from

(select t.*, row_number() over(order by empno desc) rk from emp t)

where rk<10 and rk>2

执行时间1.01秒

3.按rownum来分

select * from

(select t.*,rownum rn from emp t order by empno)

where rn<9 and rn>2;

执行时间0.1秒

个人推荐使用第三种 也主要介绍一下第三种

下面最主要介绍第三种：按rownum来分

1. rownum 分页

SELECT * FROM emp;

2. 显示rownum[oracle分配的]

SELECT e.*, ROWNUM rn FROM (SELECT * FROM emp) e;

rn相当于Oracle分配的行的ID号

3.挑选出6—10条记录

先查出1-10条记录

SELECT e.*, ROWNUM rn FROM (SELECT * FROM emp) e WHERE ROWNUM <= 10;

如果后面加上rownum>=6是不行的，

4. 然后查出6-10条记录

SELECT * FROM (SELECT e.*, ROWNUM rn FROM (SELECT * FROM emp) e WHERE ROWNUM <= 10) WHERE rn >= 6;

5. 几个查询变化

a. 指定查询列，只需要修改最里层的子查询

只查询雇员的编号和工资

SELECT * FROM (SELECT e.*, ROWNUM rn FROM (SELECT ename, sal FROM emp) e WHERE ROWNUM <= 10) WHERE rn >= 6;

b. 排序查询，只需要修改最里层的子查询

工资排序后查询6-10条数据

SELECT * FROM (SELECT e.*, ROWNUM rn FROM (SELECT ename, sal FROM emp ORDER by sal) e WHERE ROWNUM <= 10) WHERE

rn >= 6;