Question

我有一个包含如下数据的表：

pK    Customer     DateTime1                  DateTime2
1     6            2016-04-01 00:00:00.000    2016-10-09 00:00:00.000
2     6            2016-07-01 00:00:00.000    2016-10-21 00:00:00.000
3     6            2016-10-01 00:00:00.000    2016-10-20 00:00:00.000

我想查找行，当订购DateTime1时，相应的DateTime2值（在客户ID上过滤时）不遵循相同的顺序。

所以在上面的例子中，我想找到pK 3的行，因为DateTime1按升序排序，然后DateTime2不大于第2行的DateTime2。

它似乎与这个问题相似，但它处理项目的顺序而不是不平等： TSQL check if specific rows sequence exists

我尝试使用CTE声明版本

Answer 1

Declare @YourTable table (pK int,Customer int,DateTime1 datetime,DateTime2 datetime)
Insert Into @YourTable values
(1,6,'2016-04-01 00:00:00.000','2016-10-09 00:00:00.000'),
(2,6,'2016-07-01 00:00:00.000','2016-10-21 00:00:00.000'),
(3,6,'2016-10-01 00:00:00.000','2016-10-20 00:00:00.000')

;with cte as (
    Select *,Flg=Row_Number() over (Partition By Customer Order By DateTime1) - Row_Number() over (Partition By Customer Order By DateTime2) 
     From  @YourTable
)
Select pK
      ,Customer
      ,DateTime1
      ,DateTime2 
 From  cte 
 Where Flg>0

返回

pK  Customer    DateTime1               DateTime2
3   6           2016-10-01 00:00:00.000 2016-10-20 00:00:00.000

Answer 2

这似乎是row_number()：

的一个很好的应用

select t.*
from (select t.*,
             row_number() over (partition by customer order by datetime1) as seqnum_1,
             row_number() over (partition by customer order by datetime2) as seqnum_2
      from t
     ) t
where seqnum_1 <> seqnum_2;

但是这将返回所有错误排序的行，基于全局排序（在这种情况下为pk 2和3）。

您只想知道给定行上方向的变化。为此，请使用lag()：

select t.*
from (select t.*,
             lag(datetime1) over (partition by customer order by pk) as prev_dt1,
             lag(datetime2) over (partition by customer order by pk) as prev_dt2
      from t
     ) t
where (dt1 > prev_dt1 and dt2 <= prev_dt2) or
      (dt1 < prev_dt1 and dt2 >= prev_dt2);

SQL Server：在表中查找两列不连续的行

2 个答案: