在TSQL组合多个CTE(Combining multiple CTE in TSQL)

我有两个热膨胀系数，我想将它们结合在一起。 我尝试了很多，但我得到了一个语法错误。 第一部分：

declare @TimeRanges as TABLE (SessionStart datetime, SessionEnd datetime);

     with TimeRanges as (
  select @Start as StartTime, @Start + @TimeRange as EndTime
  union all
  select StartTime + @TimeRange, EndTime + @TimeRange
    from TimeRanges
    where EndTime  < @Finish )

这是第二部分：

;with cte as
(
    select SessionStartTime as changetime,1 as CC from Calls
    union all
    select SessionCloseTime,-1 from Calls
)
    select top 1 changetime,rt from
    (
    select * from cte
        cross apply 
        (select SUM(cc) as rt from cte c where c.changetime<=cte.changetime) rt         
    ) v
    order by rt desc

我想做的事：

    @Start datetime, 
    @Finish datetime,
    @TimeRange time
AS
BEGIN

    SET NOCOUNT ON;
    declare @res int SET @res = 0

    declare @TimeRanges as TABLE (SessionStart datetime, SessionEnd datetime);

    with TimeRanges as 
     (  select @Start as StartTime, @Start + @TimeRange as EndTime
        union all  
        select StartTime + @TimeRange, EndTime + @TimeRange
        from TimeRanges
        where EndTime  < @Finish ),


    cte as
    (
    select SessionStart as changetime,1 as CC from TimeRanges
    union all
    select SessionEnd,-1 from TimeRanges
    )
    select top 1 changetime,rt from
    (
    select * from cte
        cross apply 
        (select SUM(cc) as rt from cte c where c.changetime<=cte.changetime) rt         
    ) v
    order by rt desc


    select StartTime, EndTime,cte.rt
    from TimeRanges as TR left outer join
      dbo.Test as Test on TR.StartTime <= Test.SessionStartTime 
      and Test.SessionCloseTime < TR.EndTime      
    where Test.ScenarioID = 24 
    group by TR.StartTime, TR.EndTime,cte.rt    
END

第一CTE，组或按照开始时间和结束时间之间的@timerange分裂倍。 例如，开始时间11:00结束时间11:10和05:00 TIMERANGE（5分钟），然后把他们分为两个部分：11:00 - 11:05 11:05和 - 11:10。 第二CTE计数的东西这些范围。 在这里并不重要。 我试图把它们混合起来，但我到达那里的错误：

无效的列名称SessionStart“

无效的对象名称TimeRanges“

Answer 1:

因为在TimeRanges CTE，你指定的列是不同的：

with TimeRanges as 
 (  select @Start as StartTime, @Start + @TimeRange as EndTime --StartTime and EndTime
    union all  
    select StartTime + @TimeRange, EndTime + @TimeRange
    from TimeRanges
    where EndTime  < @Finish ),


cte as
(
select StartTime as changetime,1 as CC from TimeRanges --StartTime, not SessionStart
union all
select EndTime,-1 from TimeRanges --EndTime
)
select top 1 changetime,rt from
(
select * from cte
    cross apply 
    (select SUM(cc) as rt from cte c where c.changetime<=cte.changetime) rt         
) v
order by rt desc

但是你然后尝试在你的第二个查询再次参考CTE。 你不能做到这一点 - 每个CTE适用于单个查询。

你能重复一次：

with TimeRanges as 
 (  select @Start as StartTime, @Start + @TimeRange as EndTime --StartTime and EndTime
    union all  
    select StartTime + @TimeRange, EndTime + @TimeRange
    from TimeRanges
    where EndTime  < @Finish )
select StartTime, EndTime,cte.rt
from TimeRanges as TR left outer join
  dbo.Test as Test on TR.StartTime <= Test.SessionStartTime 
  and Test.SessionCloseTime < TR.EndTime      
where Test.ScenarioID = 24 
group by TR.StartTime, TR.EndTime,cte.rt  

文章来源: Combining multiple CTE in TSQL