Oracle基础教程：单行函数—数值类型函数

数值型函数
 ROUND
 TRUNC
 MOD
 CEIL
 power
ROUND(列名|表达式,n)
四舍五入到小数点后的n位
idle> select round(458.734,0),round(458.734,1),round(458.734,-1) from dual;

ROUND(458.734,0) ROUND(458.734,1) ROUND(458.734,-1)
---------------- ---------------- -----------------
      459     458.7  460

idle>

TRUNC(列名|表达式,n)
截取到小数点后的n位
idle> select trunc(458.734,0),trunc(458.734,1),trunc(458.734,-1) from dual

TRUNC(458.734,0) TRUNC(458.734,1) TRUNC(458.734,-1)
---------------- ---------------- -----------------
      458     458.7  450

idle>

MOD(m,n)
求m除以n的余数
idle> select mod(10,3) from dual;

 MOD(10,3)
----------
  1

idle>
idle> select mod(3,10) from dual;

 MOD(3,10)
----------
  3

idle>

CEIL 取整 向上补1  和trunc相反
idle> select ceil(457.001) from dual;   后面只要有小数,就进一

CEIL(457.001)
-------------
   458

idle>

power(底数,指数) 求次方

SQL> select power(10,3) from dual;

POWER(10,3)
-----------
       1000

SQL>