教你快速掌握一些经常用到的"SQL"语句

SQL> select to_char(sysdate,'YYYYMMDD W HH24:MI:SS') from dual;TO_CHAR(SYSDATE,'YY-------------------20030327 4 18:16:09SQL> select to_char(sysdate,'W') from dual;T-4

SQL> select sysdate,to_char(sysdate,'D') from dual;SYSDATE T--------- -27-MAR-03 5

select to_char(sysdate,'yyyy') from dual; --年select to_char(sysdate,'Q' from dual; --季select to_char(sysdate,'mm') from dual; --月select to_char(sysdate,'dd') from dual; --日ddd 年中的第几天WW 年中的第几个星期W 该月中第几个星期D 周中的星期几hh 小时(12)hh24 小时(24)Mi 分ss 秒

SQL> select to_char(sysdate,'day') from dual;TO_CHAR(SYSDATE,'DAY')----------------------星期四

alter session set NLS_DATE_FORMAT='YYYY-MM-DD HH24:MI:SS'

select sysdate from dual;

select trunc(sysdate) from dual;-- 得到这天的最后一秒select trunc(sysdate) + 0.99999 from dual;-- 得到小时的具体数值select trunc(sysdate) + 1/24 from dual;select trunc(sysdate) + 7/24 from dual;

select trunc(sysdate+1) from dual;select trunc(sysdate)+1 from dual;

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 date0from(select rownum rn from all_objectswhere 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;