Question

我需要检查表格中的大量数据，以确保我的Feed没有跳过任何内容。

基本上该表格包含以下列

ID日期时间价格

DateTime列中的数据在每个连续行中增加1分钟。我需要检查当前行的下一行，看看是否比该特定上下文中的查询高1分钟。

查询可能需要某种循环，然后获取下一行的副本并将其与当前的日期时间行进行比较，以确保它增加1分钟。

Answer 1

我创建了一个与您的描述相匹配的测试表，并在每行之间插入了100行，每行1分钟，如下所示：

CREATE TABLE [Test] ([Id] int IDENTITY(1,1), [Date] datetime, [Price] int);

WITH [Tally] AS (
  SELECT GETDATE() AS [Date]
  UNION ALL
  SELECT DATEADD(minute, -1, [Date]) FROM [Tally] WHERE [Date] > DATEADD(minute, -99, GETDATE())
)
INSERT INTO [Test] ([Date], [Price])
    SELECT [Date], 123 AS [Price]
    FROM [Tally]

然后我在中间删除了一条记录，以模拟丢失的一分钟：

DELETE FROM [Test]
WHERE Id = 50

现在我们可以使用此查询来查找丢失的记录：

SELECT 
    a.*
    ,CASE WHEN b.[Id] IS NULL THEN 'Next record is Missing!' ELSE CAST(b.[Id] as varchar) END AS NextId
FROM
    [Test] AS a
    LEFT JOIN [Test] AS b ON a.[Date] = DATEADD(minute,1,b.[Date])
WHERE
    b.[Id] IS NULL

resullt将如下所示：

Id          Date                    Price       NextId
----------- ----------------------- ----------- ------------------------------
49          2013-05-11 22:42:56.440 123         Next record is Missing!
100         2013-05-11 21:51:56.440 123         Next record is Missing!

(2 row(s) affected)

问题的关键解决方案是将表连接到自身，但使用datediff查找应该在下一分钟找到的记录。该表的最后一条记录当然会报告缺少下一行，因为尚未插入。

Answer 2

借用你可以使用的Q样本数据

WITH T
     AS (SELECT *,
                DATEDIFF(MINUTE, '20000101', [Date]) - 
                        DENSE_RANK() OVER (ORDER BY [Date]) AS G
         FROM   Test)
SELECT MIN([Date]) AS StartIsland,
       MAX([Date]) AS EndIsland
FROM   T
GROUP  BY G

检查表中的下一行在datetime列中增加1分钟

2 个答案: