Oracle SQL语句实现数字四舍五入取整

本文介绍Oracle中一些对数字的常用操作，包括向上向下去整、四舍五入、保留N位小数等操作，希望对大家有所帮助。

取整（向下取整）

select floor(5.534) from dual;

select trunc(5.534) from dual;

上面两种用法都可以对数字5.534向下取整，结果为5.

取整（向上取整）

select ceil(5.534) from dual;

四舍五入

SELECT round(5.534) FROM dual;

SELECT round(5.534,0) FROM dual;

SELECT round(5.534,1) FROM dual;

SELECT round(5.534,2) FROM dual;

结果分别为 6, 6, 5.5, 5.53

保留N位小数（不四舍五入）

select trunc(5.534,0) from dual;

select trunc(5.534,1) from dual;

select trunc(5.534,2) from dual;

结果分别是 5,5.5,5.53，其中保留0位小数就相当于直接取整了。

数字格式化

select to_char(12345.123,'99999999.9999') from dual;
select to_char(12345.123,'99999999.9900') from dual;

小数后第三第四为不足补0，结果为12345.1230

select to_char(0.123,'99999999.9900') from dual;

select to_char(0.123,'99999990.9900') from dual;

结果分别为 .1230, 0.1230