从Aginity工作台中的星期数和年份中获取星期的最后一天

Question

I am working in Netezza SQL.

I have got week number and year in my dataset as a combined entry. For example, "Week 3, 2017". I want to use this field to get the date for the last day of the week. In this case, I should get "21-Jan-2017".

Any thoughts on how can I do it?

Thanks.

Answer 1

Here's an example that should probably work for you:

SELECT  DATE(year_num || '-01-01') + CAST(((week_num * 7) - 1) || ' DAYS' AS INTERVAL)
  FROM  (SELECT  CAST(TRANSLATE(SUBSTR(dt, 0, INSTR(dt, ', ')), 'Week ', '') AS BYTEINT) AS week_num,
                 CAST(SUBSTR(dt, INSTR(dt, ', ') + 2) AS SMALLINT) AS year_num
           FROM  (SELECT  'Week 3, 2017' AS dt
                   UNION  ALL
                  SELECT  'Week 19, 2015' AS dt
                   UNION  ALL
                  SELECT  'Week 45, 2016' AS dt) _) _

Answer 2

Try this.

          select to_date(lpad(trim(substring(data.dt,5,100)),8,'0'),'ww, YYYY') + interval '6 days' as lastDayOfWeek

         from  (SELECT  'Week 3, 2017' AS dt
           UNION  ALL
          SELECT  'Week 19, 2015' AS dt
           UNION  ALL
          SELECT  'Week 45, 2016' AS dt) data