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
2
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