SQL获取两个日期之间的天数

-- 获取两个日期之间的天数
select trunc(sysdate) - trunc(sysdate) as days from dual;

select to_number(to_date('2021-06-10', 'yyyy-MM-dd') - to_date('2021-01-01', 'yyyy-MM-dd')) as days from dual;
select to_number(to_date('2021-06-10', 'yyyy-MM-dd HH24:mi:ss') - to_date('2021-01-01', 'yyyy-MM-dd HH24:mi:ss')) as days from dual;

-- 获取两个日期之间的月数
select months_between(to_date('2021-06-01', 'yyyy-mm-dd'),to_date('2021-01-01', 'yyyy-mm-dd')) as months from dual;
select months_between(to_date('2021-06-01', 'yyyy-MM-dd HH24:mi:ss'),to_date('2021-01-01', 'yyyy-MM-dd HH24:mi:ss')) as months from dual;