羅列出一年的星期數

N1：

with x0 as
(select to_date('2016-01-01','yyyy-mm-dd') as 年初 from dual),
x1 as (select 年初,add_months(年初,12) as 下年初 from x0),
x2 as (select 年初,下年初,下年初-年初 as 天數 from x1),
x3 as /*生成列表*/
(select 年初+(LEVEL -1) AS 日期 from x2 connect by level <=天數),
x4 as /*對數據進行轉換*/
(select 日期,to_char(日期,'DY') as 星期 from x3)
select * from x4

N2：生成當月週一作爲開始，週日作爲結束，展示如下

當月第幾周 本年第幾周      周開始         周結束
---------- --------------- -------------- --------------
   	1			22			2017/6/1	2017/6/4
	2			23			2017/6/5	2017/6/11
	3			24			2017/6/12	2017/6/18
	4			25			2017/6/19	2017/6/25
	5			26			2017/6/26	2017/6/30
  with t1 as
      (select trunc(sysdate, 'mm') start_month,
              add_months(trunc(sysdate, 'mm'), 1) - 1 end_month
         from dual)
     t2 as
      (select start_month + level - 1 months_day,
              to_char(start_month + level - 1, 'iw') locate_week
         from t1
       connect by level <= end_month - start_month + 1),
    t3 as
     (select locate_week, min(months_day) min_day, max(months_day) max_day
        from t2
       group by locate_week
       order by 1)
    select rownum         "當月第幾周",
           t3.locate_week "本年第幾周",
           t3.min_day     "周開始",
           t3.max_day     "周結束"
      from t3;

N3：構造從20170306到當前日期的時間
select to_date('20170306', 'yyyymmdd') + level - 1
  from dual
connect by to_date('20170306', 'yyyymmdd') + level - 1 < trunc(sysdate)