每周未结订单的数量

Question

我试图找到每周开放的订单数量。一个开放多周的订单应该包含在每周开放的数量中。数据看起来像下面

id open_dt    close_dt 
1 2014-01-01 07:00:00 2014-01-01 07:00:00 
2 2014-01-01 07:00:00 2014-01-02 07:00:00 
3 2014-01-02 07:00:00 2014-01-09 07:00:00 
4 2014-01-08 07:00:00 NULL 

NULL close_dt算作仍然开放，因为它是打开

应该出现在每星期

我的查询看起来像以下但它没有返回我期待的数字：

SELECT YEAR(open_dt) AS year, WEEK(open_dt) AS week, count(*) 'open' 
FROM table 
WHERE open_dt >= week(open_dt) 
OR 
(
    close_dt > week(open_dt) 
    OR close_dt IS NULL 
) 
GROUP BY YEAR(open_dt), WEEK(open_dt) 

我试图得到类似下面的结果：

year week open 
2014 1  3 
2014 2  2 
2014 3  1 
... 

欣赏任何提示或指导。

Answer 1

这是一个有助于获得日历表或星期列表的情况。让我假设你至少有一个在每个星期开：

select yw.y, yw.w, count(t.open_dt) as "Open" 
from (select distinct year(open_dt) as y, week(open_dt) as w, 
      year(open_dt) * 100 + week(open_dt) as yw 
     from table t 
    ) yw left outer join 
    table t 
    on yw.yw >= year(open_dt)*100 + week(open_dt) and 
     (yw.yw <= year(close_dt)*100 + week(close_dt) or close_dt is null) 
group by yw.y, yw.w 
order by yw.y, yw.w;