ORACLE 中NUMBER类型默认的精度

NUMBER往往没有指定P，S的值，那么默认情况下，NUMBER的P、S的值分别是多少呢？

武断的判断“如果不指定p和s，NUMBER类型，它的默认精度值为38, 默认的scale值为0”

创建表
create table test(id  number, id1 number(38,4));

插入数据
insert into test                                      
  select 12, 12 from dual union all
  select 12.123456789, 12.123456789 from dual;

查看数据
select * from test;
                                                ID                                                ID1-------------------------------------------------- --------------------------------------------------

           12.000000000000000000000000000000000000           12.0000000000000000000000000000000000000

           12.123456789000000000000000000000000000           12.1235000000000000000000000000000000000  

最大精度多少个小数

insert into test
select 12.123456789123456789123456789123456789123,
12.123456789123456789123456789123456789123
from dual;

p is the precision, or the total number of significant decimal digits, where the most

significant digit is the left-most nonzero digit, and the least significant digit is the

right-most known digit. Oracle guarantees the portability of numbers with

precision of up to 20 base-100 digits, which is equivalent to 39 or 40 decimal digits

depending on the position of the decimal point.

p是精度，有效十进制数的总位数。最大的有效数字是最左边的非零数字，而最小有效位是最右边的数字。 Oracle保证数字的可移植性

精度高达20 base-100 digits，相当于39位或40位十进制数字，取决于小数点的位置。