ORACLE分页SQL语句
一个非常好的ORACLE的分页SQL语句
select * from (select my_table.*, rownum as my_rownum from ( select yhbh, yhmc from yysf_tb_yonghxx order by yhbh) my_table where rownum <20 ) where my_rownum>=10
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其它几种分页实现:
1.根据ROWID来分
select * from t_xiaoxi where rowid in(select rid from (select rownum rn,rid from(select rowid rid,cid from
t_xiaoxi order by cid desc) where rownum<10000) where rn>9980) order by cid 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 cid desc) rk from t_xiaoxi t) where rk<10000 and rk>9980;
执行时间1.01秒
3.按ROWNUM来分
select * from(select t.*,rownum rn from(select * from t_xiaoxi order by cid desc) t where rownum<10000) where
rn>9980;执行时间0.1秒
其中t_xiaoxi为表名称,cid为表的关键字段,取按CID降序排序后的第9981-9999条记录,t_xiaoxi表有70000多条记录
个人感觉1的效率最好,3次之,2最差
oracle如何返回指定行数之间的查询结果
如何返回指定行数之间的查询结果,以实现web记录分页,在Oracle中有许多的方法,这里仅仅列出了4种,希望能对大家有所帮助,大家可以根据不同需要选择下面的script
1)select ... where rownum < 50 minus select ... where rownum < 30
这个方法因为用到了minus操作符,所以速度会受影响。
2)
SELECT results.* FROM
( SELECT t2.*, rownum rownumber FROM
( SELECT t.* FROM mv_table t WHERE ORDER BY col1) t2) results
WHERE results.rownumber BETWEEN 30 and 50 ORDER BY col1
这个方法是从一个论坛上看到的,没有亲自测试过
3)
定义cursor x, 2.fetch x a,b,c; loop ...... end loop;
其中用两个循环变量和一个FLAG变量,分别表示,当前的记录数,属于第几页的, 及第一页面。
ps;
j:=to_number(kafyf);
i:=1;
open cx;
loop fetch cx into col1,col2,col3,col4,col5,col6;
if cx%NOTFOUND then exit; end if;
if i>=j then
htp.tableRowOpen;
htp.tableData(col1);
htp.tableData(col2);
htp.tableData(col4);
htp.tableData(col5);
htp.tableData(col6);
htp.tableData(col3);
htp.tableRowClose;
i:=i+1;
if i=j+10 then l:=1; exit; end if;
else i:=i+1;
end if;
end loop;
close x;
该方法是名叫‘淼’的网友写的script,他用到了Oracle web2kit中的OWA_UTIL package。
4)How can one page forward and backwards through a table?
Externalize ROWNUM by implementing queries like this:
SELECT ...
FROM (SELECT ROWNUM rnum, ... FROM ...)
WHERE rnum BETWEEN :low AND :high AND rownum <(:high :low + 1);
where :low and :high are dynamically generated values depending on which result page the user
is viewing. Typically, they are used to show "Next 15 matches", "Previous 15 matches" links at the
bottom of each page.