Oracle数据库实用函数(二)

11.select trunc(123.458,1) from dual --123.4
12.select trunc(123.458,-1) from dual--120
13.select trunc(123.458,-4) from dual--0
14.select trunc(123.458,4) from dual --123.458
15.select trunc(123) from dual --123
16.select trunc(123,1) from dual--123
17.select trunc(123,-1) from dual--120

一下语句会经常用到，相当于不用创建表而可以插入几条数据

Select ‘Jan’ membername,’1月’ name from dual union select ‘Feb’ membername,’2月’ name from dual;

ADD_MONTHS

ADD_MONTHS(d,n)--时间点d再加上n个月