Question

我正在查看包含订单信息的数据库。我正在尝试确定从订购到装运时间超过14天的订单百分比。我很难创建每月％的列。现在我有

 Select ol.orderid, ol.productid, Month(ol.shipdate) as monthShipped,
       Year(ol.shipdate)as yearShipped, 
       (Select Count(*) From orderline ol Where datediff(ol.shipdate,o.orderdate)> 14 Group By Month(ol.shipdate), Year(ol.shipdate))/Count(*) as percentage
 From orderline ol
 Join orders o 
    on ol.orderid = o.orderid
 Group By monthShipped, yearShipped
 Order By yearShipped, monthShipped

我收到错误，说我的子查询返回多行。我不想要多行？如果我在子查询中删除了Group By，那么我得到了值，但它没有接近正确。

Answer 1

第一个问题是shipdate适用于每个订单行。我假设您的意思是每个订单的最新发货日期。以下内容在订单级别获取此信息：

 Select ol.orderid, max(ol.shipdate) as lastshipdate
 From orderline ol
 Group By ol.orderid;

要获得差异，您需要订单：

 Select ol.orderid, datediff(o.orderdate, max(ol.shipdate) ) as diff
 From orders o join
      orderline ol
      on o.orderid = ol.orderid
 Group By ol.orderid;

最后，按月获得数字和百分比：

select year(orderdate), month(orderdate),
       count(*) as numorders, sum(diff > 14) as numdelayed, avg(diff > 14) as p_dealyed
from (Select ol.orderid, datediff(o.orderdate, max(ol.shipdate) ) as diff, o.orderdate
      From orders o join
           orderline ol
           on o.orderid = ol.orderid
      Group By ol.orderid
     ) o
group by year(orderdate), month(orderdate)
order by 1, 2;

Answer 2

第一个查询返回按订单发货后14天内发货的订单项次数的百分比。

select monthShipped, yearShipped,
    (sum(greater_than_14)/count(*)) percent_exceeding_14
from (
    select
        month(ol.shipdate) as monthShipped,
        year(ol.shipdate) as yearShipped,    
        (datediff(ol.shipdate,o.orderdate) > 14) greater_than_14
    from orderline ol
    join orders o on ol.orderid = o.orderid    
) t1 group by monthShipped, yearShipped

第二个查询返回订单百分比，其中至少有一个订单行项目在按订购月份分组后的14天内发货超过14天。

select monthOrdered, yearOrdered,
    (count(g14)/count(*)) percent_exceeding_14
from (
    select 
        month(orderdate) monthOrdered, 
        year(orderdate) yearOrdered,
        greater_than_14.orderid g14
    from orders o left join (
        select orderid
        from orders o2
        where exists (
            select 1 from orderline ol
            where ol.orderid = o2.orderid
            and datediff(ol.shipdate,o2.orderdate) > 14
        )
    ) greater_than_14 on greater_than_14.orderid = o.orderid
) t1 group by monthOrdered, yearOrdered

SQL查找两个计数的百分比

2 个答案: