问在Teradata中查找给定一年中某周的开始日期和结束日期(SQL)

EN

SELECT *
  FROM Sys_Calendar."CALENDAR"
 WHERE Year_of_Calendar = CAST(SUBSTRING('201201' FROM 1 FOR 4) AS INTEGER)
   AND Week_of_Year = CAST(SUBSTRING('201201' FROM 5 FOR 2) AS INTEGER)
UNION
SELECT *
  FROM  Sys_Calendar."CALENDAR"
 WHERE Year_of_Calendar = CAST(SUBSTRING('201005' FROM 1 FOR 4) AS INTEGER)
   AND Week_of_Year = CAST(SUBSTRING('201005' FROM 5 FOR 2) AS INTEGER);

SELECT mydate                               -- 1/1/2013 --
     , TRUNC(mydate, 'iw')                  wk_starts  
     , TRUNC(mydate, 'iw') + 7 - 1/86400    wk_ends
     , TO_NUMBER (TO_CHAR (mydate, 'IW'))   ISO_wk#_iw  
     , TRUNC(mydate, 'w')                   week_start_date
     , TRUNC(mydate, 'w') + 7 - 1/86400 AS  week_end_date
 FROM
 (
  SELECT TRUNC(SYSDATE, 'YEAR')-1 + LEVEL AS mydate  -- 11/1/2013 --
    FROM dual
  CONNECT BY LEVEL <= 
  (-- First day of next year - first day of curr year --
   SELECT TRUNC(ADD_MONTHS (SYSDATE, 12), 'Y')-TRUNC(SYSDATE, 'Y') "Num of Days"   
     FROM dual
  )
)
/

SQL>

START_DATE  WK_STARTS   WK_ENDS                ISO_WK#
------------------------------------------------------------------
1/1/2013    12/31/2012  1/6/2013 11:59:59 PM    1
1/2/2013    12/31/2012  1/6/2013 11:59:59 PM    1
...
...
1/7/2013    1/7/2013    1/13/2013 11:59:59 PM   2
1/8/2013    1/7/2013    1/13/2013 11:59:59 PM   2
...
...
1/14/2013   1/14/2013   1/20/2013 11:59:59 PM   3
1/15/2013   1/14/2013   1/20/2013 11:59:59 PM   3

-- Create weekrange table
Create table Weekrange
(YearNo INT,
 WeekNo INT,
 StartDay DATETIME,
 EndDay DATETIME)
-- Populate first row
insert into WeekRange
select 2013,1, DateAdd(d,-DATEPART(dw,'1/1/2013'),'1/1/2013')+1 as FirstDay,null    -- Compute first day
update Weekrange set EndDay = DATEADD(D,6,StartDay)                                 -- Determine last day

-- Add next 52 rows
declare @id INT
set @id=2
while @id <=53
begin
    insert into Weekrange (YearNo,WeekNo) values (2013,@id)
    set @id=@id+1
    update Weekrange 
    set StartDay = DATEADD(D,1,xx.EndDay),
        EndDay = DATEADD(D,7,xx.EndDay)
    from 
    (select * from WeekRange ) xx
    where xx.weekno=weekrange.WeekNo-1
end 


select * from Weekrange