如何编写SQL查询以从1表中获取以下结果？

Question

如何编写查询以获得以下输出：

主表/源表：

Answer 1

以下是一种使用union all和聚合的方法：

select weeknumber, sum(opened) as opened, sum(closed) as closed
from ((select OpenWeekNumber as weeknumber, 1 as Opened, 0 as Closed
       from maintable
      ) union all
      (select ClosedWeekNumber as weeknumber, 0 as Opened, 1 as Closed
       from maintable
       where ClosedWeekNumber > 0
      )
     ) t
group by weeknumber
order by weeknumber;