每隔一行插入一列

Question

如果我们按日期升序组织结果，我有这个表，其中一行是Transaction Date ，第一行是checkIn ，第二行是Checkout出。

我需要将第二行值传递给另一个名为Checkout的列。 此表至少有 1000 条记录

Answer 1

您可以使用row_number() ：

select t.*
from (select t.*,
             row_number() over (partition by studentid order by transactiondate) as seqnum
      from t
     ) t
where seqnum = 2;

这假定只有studentid用于标识“第一”和“第二”行。 如果需要更多列，请将它们添加到partition by子句中。

Answer 2

如果您需要的结帐日期是按原因分组的第二个（最大）日期，并且您想挑出此日期，请尝试：

select 
  studentID,
  reason,
  max(transactionDate) as checkoutDate
from student
group by
  reason

Answer 3

尝试使用下面的查询

With CteCheckOut as(
Select
ROW_NUMBER() over (Partition by studentID Order by studentID,transactionDate) as Rownumber,
*
From student
)
Select studentID, transactionDate as CheckOutDate
From CteCheckOut
Where Rownumber%2 = 0