24.ln
返回一个数字的对数值
sql> 0select 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> 0select 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> 0select 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> 0select 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> 0select 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> 0select 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> 0select sin(1.57079) from dual.
sin(1.57079)