Oracle の日付クエリ ステートメントとは何ですか?

SQL>   select   to_char(sysdate,'YYYYMMDD   W   HH24:MI:SS')   from   dual;  
TO_CHAR(SYSDATE,'YY20030327   4   18:16:09  SQL>   
select   to_char(sysdate,'W')   from   dual;

SQL>   select sysdate,to_char(sysdate,'D')from dual;
  
SYSDATE       T

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

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

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

select sysdate from dual;

select trunc(sysdate) from dual;

select trunc(sysdate) + 0.99999 from dual;

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 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;