教你快速掌握一些经常用到的"SQL"语句

select trunc(sysdate,'mm') from dual;

select trunc(add_months(sysdate,1),'mm') from dual;

select last_day(sysdate) from dual;
select last_day(trunc(sysdate)) from dual;
select trunc(last_day(sysdate)) from dual;
select trunc(add_months(sysdate,1),'mm') - 1 from dual;

select trunc(sysdate,'yyyy')+ rn -1 date0
from
(select rownum rn from all_objects
where rownum<366);

SELECT TO_CHAR(SYSDATE,'DDD') FROM DUAL;

select add_months(sysdate,24) from dual;

select decode(to_char(last_day(trunc(sysdate,'y')+31),'dd'),'29','闰年','平年') from dual;

select decode(to_char(last_day(trunc(add_months(sysdate,24),'y')+31),
'dd'),'29','闰年','平年') from dual;

select ceil(to_number(to_char(sysdate,'mm'))/3) from dual;

select to_char(sysdate, 'Q') from dual;