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