SELECT ROWNUM r,t.* FROM (
*****************************************************************************************************************************************88
SELECT ROWNUM r,t.* FROM t_news t
FROM t_news t
WHERE r between 1 AND 3
SELECT t.* FROM t_news t ORDER BY t.n_count DESC ) t
)
values (2, '体育', '爱体育1', 10);
) t
insert into T_NEWS (ID, N_TYPE, N_TITLE, N_COUNT)
SELECT t.* FROM t_news t ORDER BY t.n_count DESC ) t
insert into T_NEWS (ID, N_TYPE, N_TITLE, N_COUNT)
--通用语法： 解析函数() over(partition by 字段 order by 字段) SELECT k.* FROM (
insert into T_NEWS (ID, N_TYPE, N_TITLE, N_COUNT)
--err
values (1, 'IT', '爱it1', 100);

WHERE ROWNUM between 4 AND 6
SELECT * FROM (
--所以必须排序，再生成行号
insert into T_NEWS (ID, N_TYPE, N_TITLE, N_COUNT)
prompt Disabling triggers for T_NEWS...
SELECT t.*,row_number() over(ORDER BY n_count DESC) r
--根据n_count从大到小排列，每页3条
WHERE r BETWEEN 4 AND 6
--error: ROWNUM必须从1开始！
values (6, '体育', '爱体育3', 20);
select t2.* from

ORDER BY t.n_count DESC

ID NUMBER,
create table T_NEWS
(select t.*,row_number()over(order by t.n_count desc) orderNumber from t_news t order by t.n_count desc)t2 where orderNumber between 1and 3;

WHERE ROWNUM between 1 AND 3
values (7, '体育', '爱体育4', 60);
N_TYPE VARCHAR2(20),

N_TITLE VARCHAR2(30),

values (5, 'IT', '爱it3', 200);
--麻烦，效率低！

复制代码 代码如下:

WHERE ROWNUM<=3
insert into T_NEWS (ID, N_TYPE, N_TITLE, N_COUNT)

ORDER BY t.n_count DESC


--分页 row_number，不是rownum
values (3, '体育', '爱体育2', 30);
prompt Loading T_NEWS...
SELECT ROWNUM r,t.* FROM (

SELECT t.* FROM t_news t ORDER BY t.n_count DESC ) t
SELECT ROWNUM r,t.* FROM t_news t
*****第二步:我用row_number() over()函数

values (4, 'IT', '爱it2', 300);
insert into T_NEWS (ID, N_TYPE, N_TITLE, N_COUNT)

SELECT t.* FROM t_news t ORDER BY t.n_count DESC ) t
insert into T_NEWS (ID, N_TYPE, N_TITLE, N_COUNT)
WHERE r BETWEEN 4 AND 6
alter table T_NEWS disable all triggers;

第一步：我先用rownum
--分页
) k
--第1页
SELECT ROWNUM r,t.* FROM (
--问题：为什么order by以后，行号是乱的？
--原因：先分配了行号，再根据n_count排序
commit;
N_COUNT NUMBER
SELECT ROWNUM r,t.* FROM (
--第2页
(

SELECT ROWNUM r,t.* FROM (
SELECT t.* FROM t_news t ORDER BY t.n_count DESC ) t