重新排序记录的聪明方法？

Question

我有一个 table 包含以下数据：

VehicleID       Time                    ContextID                   Value
--------------- ----------------------- --------------------------  -----
359586015047188 2021-02-01 07:27:14.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 07:53:38.000 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 07:53:47.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 10:24:20.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 10:26:46.000 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 10:26:55.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 10:43:53.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 10:46:01.000 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 10:46:09.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 11:02:16.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 14:39:41.777 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 14:39:42.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 14:55:48.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-02 07:52:12.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-02 07:52:12.777 SafeProtectProtectionLevel  5
359586015047188 2021-02-02 07:52:32.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-02 07:53:57.000 SafeProtectProtectionLevel  5
359586015047188 2021-02-02 07:54:10.777 SafeProtectDeviceConnected  True

如您所见，数据已及时插入。但有时，时间不正确。我需要一个查询来修复它。

如果数据一致，我将始终有一行，其中 ContextID 的值为 SafeProtectDeviceConnected，Value 的值为 True，后跟一行 ContextID 的值为 SafeProtectProtectionLevel 无论值列的值如何。

我发现我有 LAG analytics function available to access the previous row values and that I can also put one or more CASE in an order by clause

那么在对之前的结果集应用修复查询后的正确结果将是：

VehicleID       Time                    ContextID                   Value
--------------- ----------------------- --------------------------  -----
359586015047188 2021-02-01 07:27:14.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 07:53:47.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 07:53:38.000 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 10:24:20.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 10:26:55.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 10:26:46.000 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 10:43:53.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 10:46:09.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 10:46:01.000 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 11:02:16.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-01 14:39:42.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-01 14:39:41.777 SafeProtectProtectionLevel  5
359586015047188 2021-02-01 14:55:48.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-02 07:52:12.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-02 07:52:12.777 SafeProtectProtectionLevel  5
359586015047188 2021-02-02 07:52:32.777 SafeProtectDeviceConnected  False
359586015047188 2021-02-02 07:54:10.777 SafeProtectDeviceConnected  True
359586015047188 2021-02-02 07:53:57.000 SafeProtectProtectionLevel  5

基本上，如果我们查看上面重新排序的结果集，特别是从上到下的值列，我们应该有一个 True 值，后跟一个或多个带有数值的行，然后是一个 False值

到目前为止我尝试过的是使用 ORDER BY t.VehiculeID, /*dbo.ContextDetail.Time*/ CASE WHEN t.ContextID='SafeProtectDeviceConnected' AND t.Value='True' THEN 1 END, CASE WHEN t.ContextID='SafeProtectProtectionLevel' THEN 2 END, CASE WHEN t.ContextID='SafeProtectDeviceConnected' AND t.Value='False' THEN 3 END

但它（显然）给了我所有 False 行，然后是所有 numeric rows，然后是剩余的 True 值。

这个问题是空白和孤岛吗？
解决这个问题的正确方法是什么？

Answer 1

只要必须分组的行之间的时间不重叠，那么你可以使用Time列对行进行分组，并使用case表达式来确定一个内的排序单组。下面的解决方案使用通用 table 表达式计算这些新列，以便于选择和排序。

示例数据

create table log
(
  VehicleID bigint,
  Time datetime,
  ContextID nvarchar(50),
  Value nvarchar(10)
);

insert into log (VehicleID, Time, ContextID, Value) values
(359586015047188, '2021-02-01 07:27:14.777', 'SafeProtectDeviceConnected', 'False'),
(359586015047188, '2021-02-01 07:53:38.000', 'SafeProtectProtectionLevel', '5'),
(359586015047188, '2021-02-01 07:53:47.777', 'SafeProtectDeviceConnected', 'True'),
(359586015047188, '2021-02-01 10:24:20.777', 'SafeProtectDeviceConnected', 'False'),
(359586015047188, '2021-02-01 10:26:46.000', 'SafeProtectProtectionLevel', '5'),
(359586015047188, '2021-02-01 10:26:55.777', 'SafeProtectDeviceConnected', 'True'),
(359586015047188, '2021-02-01 10:43:53.777', 'SafeProtectDeviceConnected', 'False'),
(359586015047188, '2021-02-01 10:46:01.000', 'SafeProtectProtectionLevel', '5'),
(359586015047188, '2021-02-01 10:46:09.777', 'SafeProtectDeviceConnected', 'True'),
(359586015047188, '2021-02-01 11:02:16.777', 'SafeProtectDeviceConnected', 'False'),
(359586015047188, '2021-02-01 14:39:41.777', 'SafeProtectProtectionLevel', '5'),
(359586015047188, '2021-02-01 14:39:42.777', 'SafeProtectDeviceConnected', 'True'),
(359586015047188, '2021-02-01 14:55:48.777', 'SafeProtectDeviceConnected', 'False'),
(359586015047188, '2021-02-02 07:52:12.777', 'SafeProtectDeviceConnected', 'True'),
(359586015047188, '2021-02-02 07:52:12.777', 'SafeProtectProtectionLevel', '5'),
(359586015047188, '2021-02-02 07:52:32.777', 'SafeProtectDeviceConnected', 'False'),
(359586015047188, '2021-02-02 07:53:57.000', 'SafeProtectProtectionLevel', '5'),
(359586015047188, '2021-02-02 07:54:10.777', 'SafeProtectDeviceConnected', 'True');

解决方案

备注：你可以稍微缩小case表达式。为清楚起见，此处完整写出。

with cte as
(
  select l.VehicleID,
         l.Time,
         l.ContextID,
         l.Value,
         (row_number() over(order by l.Time)-1)/3 as GroupNum,
         case
           when l.ContextID = 'SafeProtectDeviceConnected' and l.Value = 'False' then 1
           when l.ContextID = 'SafeProtectDeviceConnected' and l.Value = 'True'  then 2
           when l.ContextID = 'SafeProtectProtectionLevel'                       then 3
         end as GroupSort
  from log l
)
select cte.VehicleID,
       cte.Time,
       cte.ContextID,
       cte.Value
from cte
order by cte.GroupNum,
         cte.GroupSort;

结果

VehicleID        Time                     ContextID                   Value
---------------  -----------------------  --------------------------  -----
359586015047188  2021-02-01 07:27:14.777  SafeProtectDeviceConnected  False
359586015047188  2021-02-01 07:53:47.777  SafeProtectDeviceConnected  True
359586015047188  2021-02-01 07:53:38.000  SafeProtectProtectionLevel  5
359586015047188  2021-02-01 10:24:20.777  SafeProtectDeviceConnected  False
359586015047188  2021-02-01 10:26:55.777  SafeProtectDeviceConnected  True
359586015047188  2021-02-01 10:26:46.000  SafeProtectProtectionLevel  5
359586015047188  2021-02-01 10:43:53.777  SafeProtectDeviceConnected  False
359586015047188  2021-02-01 10:46:09.777  SafeProtectDeviceConnected  True
359586015047188  2021-02-01 10:46:01.000  SafeProtectProtectionLevel  5
359586015047188  2021-02-01 11:02:16.777  SafeProtectDeviceConnected  False
359586015047188  2021-02-01 14:39:42.777  SafeProtectDeviceConnected  True
359586015047188  2021-02-01 14:39:41.777  SafeProtectProtectionLevel  5
359586015047188  2021-02-01 14:55:48.777  SafeProtectDeviceConnected  False
359586015047188  2021-02-02 07:52:12.777  SafeProtectDeviceConnected  True
359586015047188  2021-02-02 07:52:12.777  SafeProtectProtectionLevel  5
359586015047188  2021-02-02 07:52:32.777  SafeProtectDeviceConnected  False
359586015047188  2021-02-02 07:54:10.777  SafeProtectDeviceConnected  True
359586015047188  2021-02-02 07:53:57.000  SafeProtectProtectionLevel  5

Fiddle 查看实际情况。

Answer 2

试试这个：

ORDER BY VehicleID, CAST(CONVERT(NVARCHAR(8), [Time], 112) AS BIGINT)*10000 + DATEPART(HOUR, [Time])* 100 + DATEPART(MINUTE, [Time]), CASE WHEN ContextID = 'SafeProtectDeviceConnected' AND [Value] = 'False' THEN 1 WHEN ContextID = 'SafeProtectDeviceConnected' AND [Value] = 'True' THEN 2 ELSE 3 END

与您的方法的主要区别：首先，我详细说明了我的订单中小于一分钟的所有内容，因为您提到过，那个时间可能有误。然而，据我所知（之后）时间似乎还可以但不是唯一的 - 所以按时间排序也应该可以解决问题。其次，我创建了一个 case 语句来考虑上下文和价值，而不是每列一个 case - 你想按两列的组合排序，而不是分别按每一列排序。所以组合 Connected + False 得到 1，Connected + True 得到 2，其他所有东西得到 3。在您的查询中，您创建了三个案例，其中 return 一个值或 NULL（CASE... END 没有其他），所以毕竟您添加了三个值来排序。

重新排序记录的聪明方法？

Clever way to reorder records?

sql-server

gaps-and-islands