包括日期边界以细分选择结果答案

【问题标题】：Include date boundaries to segment select results包括日期边界以细分选择结果
【发布时间】：2014-03-24 11:58:53
【问题描述】：

我想在同一行中返回不同时间范围内特定度量的结果。例如“过去 30 天”、“过去 7 天”、“过去 3 天”。为此，我最初使用了UNION 函数，并为每个时间范围创建了多个子查询。这样做的缺点是我收集了 3 次相同的数字，因此会增加运行时间。

一位同事建议我使用CASE 函数来分割时间范围。我最初想按如下方式实现它：

select tp.Name, 
    case when pub.Date between DATEADD(day, -31, getdate()) and DATEADD(day, -1, getdate()) 
        then SUM(Impressions) else 0 end 'Last 30 days Impressions',
    case when pub.Date between DATEADD(day, -31, getdate()) and DATEADD(day, -1, getdate()) 
        then SUM(Revenue * rler.Rate) else 0 end 'Last 30 days Revenues',
    case when pub.Date between DATEADD(day, -8, getdate()) and DATEADD(day, -1, getdate()) 
        then SUM(Impressions) else 0 end 'Last 7 days Impressions',
    case when pub.Date between DATEADD(day, -8, getdate()) and DATEADD(day, -1, getdate()) 
        then SUM(Revenue * rler.Rate) else 0 end 'Last 7 days Revenues',
    case when pub.Date between DATEADD(day, -4, getdate()) and DATEADD(day, -1, getdate()) 
        then SUM(Impressions) else 0 end 'Last 3 days Impressions',
    case when pub.Date between DATEADD(day, -4, getdate()) and DATEADD(day, -1, getdate()) 
        then SUM(Revenue * rler.Rate) else 0 end 'Last 3 days Revenues'

from ...

where ...

group by tp.Name, tp.Kind, pub.Date

order by 'Last 30 days Impressions'

不幸的是，这将为每个名称、种类和日期返回一行，这不是我想要的。我认为这个问题取决于GROUP BY 调用中的pub.Date。我应该怎么做才能克服这个问题？

【问题讨论】：

标签： sql date case between

【解决方案1】：

由于时间重叠，您无法完全执行同事的建议。你可以做不重叠的范围，像这样：

select tp.Name, 
        (case when pub.Date between DATEADD(day, -3, getdate()) and DATEADD(day, -1, getdate()) 
              then 'Last 3 days Impressions'
              when pub.Date between DATEADD(day, -7, getdate()) and DATEADD(day, -1, getdate()) 
              then '4-7 days Impressions'
              when pub.Date between DATEADD(day, -31, getdate()) and DATEADD(day, -1, getdate()) 
              then '8-31 days Impressions'
              else 'Older'
         end) as TimeRange,
       SUM(Impressions) as NumImpressions,
       . . . 
from . . .
where . . .
group by tp.Name, 
         (case when pub.Date between DATEADD(day, -3, getdate()) and DATEADD(day, -1, getdate()) 
               then 'Last 3 days Impressions'
               when pub.Date between DATEADD(day, -7, getdate()) and DATEADD(day, -1, getdate()) 
               then '4-7 days Impressions'
               when pub.Date between DATEADD(day, -31, getdate()) and DATEADD(day, -1, getdate()) 
               then '8-31 days Impressions'
               else 'Older'
          end)

【讨论】：

【解决方案2】：

我正在回答我自己的问题。结果可以使用以下代码实现：

select tp.Name, 
    sum(case when pub.Date between DATEADD(day, -31, getdate()) and DATEADD(day, -1, getdate()) 
        then Impressions else 0 end) 'Last 30 days Impressions',
    sum(case when pub.Date between DATEADD(day, -31, getdate()) and DATEADD(day, -1, getdate()) 
        then (Revenue * rler.Rate) else 0 end) 'Last 30 days Revenues',
    sum(case when pub.Date between DATEADD(day, -8, getdate()) and DATEADD(day, -1, getdate()) 
        then Impressions else 0 end) 'Last 7 days Impressions',
    sum(case when pub.Date between DATEADD(day, -8, getdate()) and DATEADD(day, -1, getdate()) 
        then (Revenue * rler.Rate) else 0 end) 'Last 7 days Revenues',
    sum(case when pub.Date between DATEADD(day, -4, getdate()) and DATEADD(day, -1, getdate()) 
        then Impressions else 0 end) 'Last 3 days Impressions',
    sum(case when pub.Date between DATEADD(day, -4, getdate()) and DATEADD(day, -1, getdate()) 
        then (Revenue * rler.Rate) else 0 end) 'Last 3 days Revenues'

from ...

where ...

group by tp.Name, tp.Kind

order by 'Last 30 days Impressions' desc

【讨论】：