–返回ASCII码
select ASCII(‘A’) “A的ASCII码” ,ASCII(‘a’) “a的ASSCII码” from dual ;
–反向
select CHR(65) from dual;
–连接两个字符串,如果一个为空则返回有值的
select concat(‘Oracle’,’11g’) “合并后” from dual;
–返回字符串中 每个 单词首字母大写
select initcap(‘oracle universal installer’) “首字母大写后” from dual;
–返回一个字符在字符串’j’中从第6个开始第3次出现的位置
select INSTR (‘jjjjjireutoilkjsdflkdsjfoiuewrlkdsjflkoieuroiu’,’j’,-6,3) from dual ;
–返回字符串长度
select length(‘oituoireutoilkjsdflkdsjfoiuewrlkdsj’) from dual; –6为正数时,j的位置
select length(‘jjjjjireutoilkj’) from dual; –6为负数时,j的位置,从左往右数,但是返回值是正数位置
–去掉一个字符串从左边开始,包含’iuyu’的字符
select LTRIM(‘iuuuuyyuyuyuyuyuidsfdysytu’,’iuyu’) from dual;
–替代字符串中指定的字符为指定的字符
select replace (‘opopiiuopoijiuu’,’o’,’A’) from Dual;
——————————————-数字类函数
–返回大于或等于n的 最小整数
select ceil(9.02) from dual; –向上取整
–返回小于或等于n 的 最大整数
select floor(8.6345) from dual;–向下取整
–sign 若正 返回1 若负 返回-1
select sign(9) from dual; –可以根据状态,比较大小
FLOOR——对给定的数字取整数位–向下取整
SQL> select floor(2345.67) from dual;
FLOOR(2345.67)
————–
2345
CEIL– 返回大于或等于给出数字的最小整数–向上取整
SQL> select ceil(3.1415927) from dual;
CEIL(3.1415927)
—————
4
ROUND——按照指定的精度进行四舍五入
SQL> select round(3.1415926,4) from dual;
ROUND(3.1415926,4)
——————
3.1416
TRUNC——按照指定的精度进行截取一个数
SQL> select trunc(3.1415926,4) from dual;
ROUND(3.1415926,4) 3.1415
——————
——————————————————————
select sysdate from dual;
–取结果集前51条
select *
from (select a.factorvalue,’1′,’105A’
from productdata.femriskfactorlistb a
where 1 = 1
and a.riskcode = ‘106001003’
and a.factortype = ‘TextAge’
order by a.factorvalueorder)
where rownum <= 51;
—-正则替换
select regexp_replace(’87Y’,'[^0-9]’) from dual;—-87
–查询重复记录并删除
DELETE SDBANKMAPPINGTEST WHERE ID IN(
SELECT (comcode) from SDBANKMAPPINGTEST
group by (comcode) having count(*)>1 );
— Add/modify columns
alter table test_daoru rename column NEW_FIELD_NAME to name;
–删除一个字段
alter table test_daoru
drop column ;
—快读插入N条数据—————————————————————————–
declare
i integer; –定义变量
begin
i := 18;
loop
/* 插入数据 feeyear缴费期限 period保险期间 */
insert into sh_1044_nv(textage,sex,feeyear,period,amnt,cod1)
values(
TO_CHAR(i||’Y’),’1′,’1000Y’,’10Y’,”,’10000′
);
/* 参数递增 */
i := i + 1;
/* 停止条件 */
exit when i > 60;
end loop;
commit;
end;
—Oracle自动序列号——————————————–
create sequence <序列名称>
start with <起始数>
increment by <增长量>
[maxvalue 值]
[minvalue 值]
[cycle 当到达最大值的时候，将继续从头开始]
[Nocycle — 一直累加，不循环]
[Cache ]
———————————————————-
–创建一个方法通过生日得到年龄
create or replace function GetAge(brithday varchar2) return number as
v_Age number(3);
begin
select to_char(sysdate, ‘yyyy’) –
to_char(to_date(brithday, ‘yyyy-mm-dd’), ‘yyyy’) +
decode(sign(to_char(sysdate, ‘mmdd’) –
to_char(to_date(brithday, ‘yyyy-mm-dd’), ‘mmdd’)),
-1,
-1,
0,
0,
1,
0)
into v_Age
from dual;
return v_Age;
end;
———————————————————-
–3.查出锁定表的sid, serial#,os_user_name, machine_name, terminal，锁的type,mode
SELECT s.sid, s.serial#, s.username, s.schemaname, s.osuser, s.process, s.machine,
s.terminal, s.logon_time, l.type
FROM v$session s,v$lock l
WHERE s.sid = l.sid
AND s.username IS NOT NULL
ORDER BY sid;
———————————————————-
–锁表查询
SELECT object_name, machine, s.sid, s.serial#
FROM gv$locked_object l, dba_objects o, gv$session s
WHERE l.object_id = o.object_id
AND l.session_id = s.sid;
–==================
–释放SESSION SQL:
–alter system kill session ‘sid, serial#’;
ALTER system kill session ’23, 1647′;
———————————————————-
—查看数据库空间大小
select a.tablespace_name,
a.bytes / 1024 / 1024 “Sum MB”,
(a.bytes – b.bytes) / 1024 / 1024 “used MB”,
b.bytes / 1024 / 1024 “free MB”,
round(((a.bytes – b.bytes) / a.bytes) * 100, 2) “percent_used”
from (select tablespace_name, sum(bytes) bytes
from dba_data_files
group by tablespace_name) a,
(select tablespace_name, sum(bytes) bytes, max(bytes) largest
from dba_free_space
group by tablespace_name) b
where a.tablespace_name = b.tablespace_name
order by ((a.bytes – b.bytes) / a.bytes) desc;
———————————————————-
–修改字段长度
alter table test_feilv_01 modify ( textage varchar2(10))
———————————————————-
–汇总
select decode(grouping(a.scene_id) + grouping(a.enter_id),
1,’小计’,
2,’总计’,
a.enter_id) “公司编码”,
decode(grouping(a.scene_id), 1, count(*) || ‘条’, a.scene_id) “报文编号”
–sum(f_pagesnumber) sum_pagesnumbers
from tft_xsl_template a
group by rollup(a.enter_id, a.scene_id);
———————————————————-
–oracle 中的替换
regexp_replace(1,2,3,4,5,6)
语法说明：1：字段 2：替换的字段 3：替换成什么 4：起始位置（默认从1开始） 5：替换的次数（0是无限次） 6：不区分大小写
———————————————————-
/*1. 利用游标循环更新、删除MemberAccount表中的数据*/
DECLARE My_Cursor CURSOR –定义游标
FOR (SELECT * FROM dbo.MemberAccount) –查出需要的集合放到游标中
OPEN My_Cursor; –打开游标
FETCH NEXT FROM My_Cursor ; –读取第一行数据
WHILE @@FETCH_STATUS = 0
BEGIN
–UPDATE dbo.MemberAccount SET UserName = UserName + ‘A’ WHERE CURRENT OF My_Cursor; –更新
–DELETE FROM dbo.MemberAccount WHERE CURRENT OF My_Cursor; –删除
FETCH NEXT FROM My_Cursor; –读取下一行数据
END
CLOSE My_Cursor; –关闭游标
DEALLOCATE My_Cursor; –释放游标
GO
/*2. 利用游标循环更新MemberService表中的数据（更新每个用户所购买服务的时间）*/
DECLARE @UserId varchar(50)
DECLARE My_Cursor CURSOR –定义游标
FOR (SELECT UserId FROM dbo.MemberAccount) –查出需要的集合放到游标中
OPEN My_Cursor; –打开游标
FETCH NEXT FROM My_Cursor INTO @UserId; –读取第一行数据(将MemberAccount表中的UserId放到@UserId变量中)
WHILE @@FETCH_STATUS = 0 BEGIN PRINT @UserId; –打印数据(打印MemberAccount表中的UserId)
UPDATE dbo.MemberService SET ServiceTime = DATEADD(Month, 6, getdate()) WHERE UserId = @UserId; –更新数据
FETCH NEXT FROM My_Cursor INTO @UserId; –读取下一行数据(将MemberAccount表中的UserId放到@UserId变量中)
END CLOSE My_Cursor; –关闭游标
DEALLOCATE My_Cursor; –释放游标
GO
———————————————————-
