oracle常用函数 [oracle+110个常用函数]

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 XXX电话 from dual;

XXX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 gao.nchar_tst;

NAME LENGTH(NAME) ADDR LENGTH(ADDR) SAL LENGTH(TO_CHAR(SAL))

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

XXX 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(H

----------

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

ST_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.mm.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