如何计算2行多个场景之间的天数

Question

我想从这样的表中计算几天：

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我有2列状态和日期，我需要计算一行有1和3的状态的天数，例如：第一行有staus 1第二行有状态2这两行之间的差异是3天，同样的八九排。所有这些计算我都要在sql中做。

Answer 1

如果您有可用的分析（aka窗口）函数（Oracle，SQL Server，Postgresql，MySQL），则可以执行此操作。基本思想是（使用Oracle SQL方言）：

select
sum(trunc(next_date) - trunc(dat))
from (
select 
  status,
  dat,
  lead(dat) over (order by dat asc) next_date
from
      (  -- This is a "fake" data table
      select 1 as status, to_date('15/2/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 2 as status, to_date('18/2/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 3 as status, to_date('20/2/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 2 as status, to_date('23/2/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 4 as status, to_date('24/2/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 7 as status, to_date('27/2/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 9 as status, to_date('28/2/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 3 as status, to_date('1/3/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 14 as status, to_date('4/3/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 15 as status, to_date('7/3/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 1 as status, to_date('10/3/2018' ,'dd/mm/yyyy') dat from dual
      union all
      select 2 as status, to_date('14/3/2018' ,'dd/mm/yyyy') dat from dual
      ) d
  ) d2
where
  status in (1, 3);

其他方言可能略有不同，但想法是一样的。

Answer 2

这适用于sql-server 2012.我无法找到任何会阻止此语法的文档。

<script src="https://cdnjs.cloudflare.com/ajax/libs/date-fns/1.29.0/date_fns.js"></script>
<input type="date" onChange="getDate();" id="oldDate" />
<input type="date" id="newDate" />