Oracle 函数大全

1.ascii 返回与指定的字符对应的十进制数;

sql> select ascii('a') a,ascii('a') a,ascii('0') zero,ascii(' ') space from dual;

a         a      zero     space
--------- --------- --------- ---------
65        97        48        32

2.chr 给出整数,返回对应的字符;

sql> select chr(54740) zhao,chr(65) chr65 from dual;

zh c
-- -
赵 a

3.concat 连接两个字符串;

sql> select concat('010-','88888888')||'转23'  高乾竞电话 from dual;

高乾竞电话
----------------
010-88888888转23

4.initcap 返回字符串并将字符串的第一个字母变为大写;

sql> select initcap('smith') upp from dual;

upp
-----
smith

5.instr(c1,c2,i,j) 在一个字符串中搜索指定的字符,返回发现指定的字符的位置;

c1    被搜索的字符串
c2    希望搜索的字符串
i     搜索的开始位置,默认为1
j     出现的位置,默认为1
sql> select instr('oracle traning','ra',1,2) instring from dual;

instring
---------
9

6.length 返回字符串的长度;

sql> select name,length(name),addr,length(addr),sal,length(to_char(sal)) from .nchar_tst;

name   length(name) addr             length(addr)       sal length(to_char(sal))
------ ------------ ---------------- ------------ --------- --------------------
高乾竞            3 北京市海锭区                6   9999.99                    7

7.lower 返回字符串,并将所有的字符小写

sql> select lower('aabbccdd')aabbccdd from dual;

aabbccdd
--------
aabbccdd

8.upper 返回字符串,并将所有的字符大写

sql> select upper('aabbccdd') upper from dual;

upper
--------
aabbccdd

9.rpad和lpad(粘贴字符)

rpad  在列的右边粘贴字符
lpad  在列的左边粘贴字符
sql> select lpad(rpad('gao',10,'*'),17,'*')from dual;

lpad(rpad('gao',1
-----------------
*******gao*******
不够字符则用*来填满

10.ltrim和rtrim

ltrim  删除左边出现的字符串
rtrim  删除右边出现的字符串
sql> select ltrim(rtrim('   gao qian jing   ',' '),' ') from dual;

ltrim(rtrim('
-------------
gao qian jing

11.substr(string,start,count)

取子字符串,从start开始,取count个
sql> select substr('13088888888',3,8) from dual;

substr('
--------
08888888

12.replace('string','s1','s2')

string   希望被替换的字符或变量
s1       被替换的字符串
s2       要替换的字符串

sql> select replace('he love you','he','i') from dual;

replace('heloveyou','he','i')
------------------------------
i love you

13.soundex 返回一个与给定的字符串读音相同的字符串

sql> create table table1(xm varchar(8));
sql> insert into table1 values('weather');
sql> insert into table1 values('wether');
sql> insert into table1 values('gao');

sql> select xm from table1 where soundex(xm)=soundex('weather');

xm
--------
weather
wether

14.trim('s' from 'string')

leading   剪掉前面的字符
trailing  剪掉后面的字符
如果不指定,默认为空格符

15.abs 返回指定值的绝对值

sql> select abs(100),abs(-100) from dual;

abs(100) abs(-100)
--------- ---------
100       100

16.acos 给出反余弦的值

sql> select acos(-1) from dual;

acos(-1)
---------
3.1415927

17.asin 给出反正弦的值

sql> select asin(0.5) from dual;

asin(0.5)
---------
.52359878

18.atan 返回一个数字的反正切值

sql> select atan(1) from dual;

atan(1)
---------
.78539816

19.ceil 返回大于或等于给出数字的最小整数

sql> select ceil(3.1415927) from dual;

ceil(3.1415927)
---------------
4

20.cos 返回一个给定数字的余弦

sql> select cos(-3.1415927) from dual;

cos(-3.1415927)
---------------
-1

21.cosh 返回一个数字反余弦值

sql> select cosh(20) from dual;

cosh(20)
---------
242582598

22.exp 返回一个数字e的n次方根

sql> select exp(2),exp(1) from dual;

exp(2)    exp(1)
--------- ---------
7.3890561 2.7182818

23.floor 对给定的数字取整数

sql> select floor(2345.67) from dual;

floor(2345.67)
--------------
2345

24.ln 返回一个数字的对数值

sql> select ln(1),ln(2),ln(2.7182818) from dual;

ln(1)     ln(2) ln(2.7182818)
--------- --------- -------------
0 .69314718     .99999999

25.log(n1,n2) 返回一个以n1为底n2的对数

sql> select log(2,1),log(2,4) from dual;

log(2,1)  log(2,4)
--------- ---------
0         2

26.mod(n1,n2) 返回一个n1除以n2的余数

sql> select mod(10,3),mod(3,3),mod(2,3) from dual;

 

mod(10,3)  mod(3,3)  mod(2,3)

--------- --------- ---------

1         0         2

27.power 返回n1的n2次方根

sql> select power(2,10),power(3,3) from dual;

power(2,10) power(3,3)

----------- ----------

1024         27

28.round和trunc

按照指定的精度进行舍入

sql> select round(55.5),round(-55.4),trunc(55.5),trunc(-55.5) from dual;

round(55.5) round(-55.4) trunc(55.5) trunc(-55.5)

----------- ------------ ----------- ------------

56          -55          55          -55

29.sign 取数字n的符号,大于0返回1,小于0返回-1,等于0返回0

sql> select sign(123),sign(-100),sign(0) from dual;

sign(123) sign(-100)   sign(0)

--------- ---------- ---------

1         -1         0

30.sin 返回一个数字的正弦值

sql> select sin(1.57079) from dual;

sin(1.57079)

------------

1

31.sigh 返回双曲正弦的值

sql> select sin(20),sinh(20) from dual;

 

sin(20)  sinh(20)

--------- ---------

.91294525 242582598

32.sqrt 返回数字n的根

sql> select sqrt(64),sqrt(10) from dual;

sqrt(64)  sqrt(10)

--------- ---------

8 3.1622777

33.tan 返回数字的正切值

sql> select tan(20),tan(10) from dual;

tan(20)   tan(10)

--------- ---------

2.2371609 .64836083

34.tanh

返回数字n的双曲正切值

sql> select tanh(20),tan(20) from dual;

tanh(20)   tan(20)

--------- ---------

1 2.2371609

35.trunc

按照指定的精度截取一个数

sql> select trunc(124.1666,-2) trunc1,trunc(124.16666,2) from dual;

trunc1 trunc(124.16666,2)

--------- ------------------

100             124.16

36.add_months

增加或减去月份

sql> select to_char(add_months(to_date('199912','yyyymm'),2),'yyyymm') from dual;

to_cha

------

200002

sql> select to_char(add_months(to_date('199912','yyyymm'),-2),'yyyymm') from dual;

to_cha

------

199910

37.last_day

返回日期的最后一天

sql> select to_char(sysdate,'yyyy.mm.dd'),to_char((sysdate)+1,'yyyy.mm.dd') from dual;

to_char(sy to_char((s

---------- ----------

2004.05.09 2004.05.10

sql> select last_day(sysdate) from dual;

last_day(s

----------

31-5月 -04

38.months_between(date2,date1)

给出date2-date1的月份

sql> select months_between('19-12月-1999','19-3月-1999') mon_between from dual;

mon_between

-----------

9

sql>selectmonths_between(to_date('2000.05.20','yyyy.mm.dd'),to_date('2005.05.20','yyyy.dd')) mon_betw from dual;

mon_betw

---------

-60

39.new_time(date,'this','that')

给出在this时区=other时区的日期和时间

sql> select to_char(sysdate,'yyyy.mm.dd hh24:mi:ss') bj_time,to_char(new_time

2  (sysdate,'pdt','gmt'),'yyyy.mm.dd hh24:mi:ss') los_angles from dual;

bj_time             los_angles

------------------- -------------------

2004.05.09 11:05:32 2004.05.09 18:05:32

40.next_day(date,'day')

给出日期date和星期x之后计算下一个星期的日期

sql> select next_day('18-5月-2001','星期五') next_day from dual;

next_day

----------

25-5月 -01

41.sysdate 用来得到系统的当前日期

sql> select to_char(sysdate,'dd-mm-yyyy day') from dual;

to_char(sysdate,'

-----------------

09-05-2004 星期日

trunc(date,fmt)按照给出的要求将日期截断,如果fmt='mi'表示保留分,截断秒

sql> select to_char(trunc(sysdate,'hh'),'yyyy.mm.dd hh24:mi:ss') hh,

2  to_char(trunc(sysdate,'mi'),'yyyy.mm.dd hh24:mi:ss') hhmm from dual;

hh                  hhmm

------------------- -------------------

2004.05.09 11:00:00 2004.05.09 11:17:00

42.chartorowid 将字符数据类型转换为rowid类型

sql> select rowid,rowidtochar(rowid),ename from scott.emp;

rowid              rowidtochar(rowid) ename

------------------ ------------------ ----------

aaaafkaacaaaaeqaaa aaaafkaacaaaaeqaaa smith

aaaafkaacaaaaeqaab aaaafkaacaaaaeqaab allen

aaaafkaacaaaaeqaac aaaafkaacaaaaeqaac ward

aaaafkaacaaaaeqaad aaaafkaacaaaaeqaad jones