用最小日期和最大日期合并记录

Question

I have two rows of data in a SQL Server query and need to consolidate them into one column by criteria of min date for one column and max date for the second column.

Example data:

OrderID   PrevCFS   NewCFS   ChangeTime
---------------------------------------------------
   1        75         25    2018-10-31 08:00:00
   2        25          0    2018-10-31 09:00:00

I need them to be combined using the earliest date for PrevCFS and the latest date for NewCFS as there could be more than two records:

Results:

PrevCFS   NewCFS   ChangeTime
---------------------------------------------------
  75        0      2018-10-31 09:00:00

The OrderID and Change time are not important in the results.

Answer 1

You can try to use MAX and MIN aggregate function.

SELECT MAX(PrevCFS) PrevCFS,
       MIN(NewCFS) NewCFS,
       MAX(ChangeTime) ChangeTime
FROM T

Answer 2

select
  (
    select top 1 PrevCFS
    from MyTable
    order by ChangeTime asc
  )
  ,
  (
    select top 1 NewCFS
    from MyTable
    order by ChangeTime desc
  )

Answer 3

You can get the most recent columns by ordering descending, and the older columns by ordering ascending.

Here is one way to combine them:

select top (1) eprev.OldCFS, e.NewCFS, e.ChangeTime
from example e cross join
     (select top (1) e2.*
      from example e2
      order by e.ChangeTime asc
     ) eprev
order by e.ChangeTime desc

Answer 4

Is this helpful.?

    Declare @T Table(OrderId int,PrevCFS int, NewCFS int,ChangeTime DATETIME)

    Insert into @T
    SELECT 1,75,25,'2018-10-31 08:00:0' Union All
    SELECT 2,25,0,'2018-10-31 09:00:00'

    Select t1.PrevCFS,t2.NewCFS,t2.ChangeTime from @T t1
    INNER JOIN @T t2 on t1.NewCFS=t2.PrevCFS

output:

    PrevCFS    NewCFS           ChangeTime
------------------------------------------------
      75         0       2018-10-31 09:00:00.000