round、trunc、ceil、floor、mod
roun四捨五入
SELECT round(45.987) FROM dual;

SELECT round(45.187,2) FROM dual;

SELECT round(55.187,-2) FROM dual;

SELECT round(45.187,-2) FROM dual;

ceil只入不捨
只能入到整數部分
SELECT ceil(45.6) FROM dual;
SELECT ceil(45.1) FROM dual;

floor只舍不入
SELECT floor(45.6) FROM dual;
SELECT floor(45.1) FROM dual;

mod 取模運算
SQL> SELECT mod(45,6) FROM dual;