Question

我正在尝试设计一个按日期对记录进行分组的查询。我有记录代表已发生的事件。如果事件发生在同一部分并且相互之间的距离不超过50毫秒，则应将它们分组。我表格的重要部分如下：

ID | sectionID | eventDateTime | ...

我想我想要按sectionID和eventDateTime分组（sectionID将跨越ID）并使用having子句来定义我的时间分组约束。我也认为查询可能无法做到这一点。我看到DATEDIFF()，但只对日期的单个组件进行计算。任何帮助将不胜感激。

Answer 1

您是否正在寻找类似于以下内容的内容：

With [Events] As
    (
    Select 1 As Id, 5 As SectionId, Cast('2011-05-04 23:59:59.950' As DateTime) As EventDateTime
    Union All Select 2, 5, '2011-05-05 00:00:00.000'
    Union All Select 3, 5, '2011-05-05 00:00:00.049'
    )
    , TaggedData As
    (
    Select E1.Id, E1.sectionID
        , Cast(Coalesce(E2.EventDateTime, E1.EventDateTime) As Date) As TagEventDateTime
    From [Events] As E1
        Left Join [Events] As E2
            ON E2.sectionID = E1.sectionID
                And E2.Id <> E1.Id
                And E2.EventDateTime >= DateAdd(ms, -50, E1.EventDateTime)
                And E2.EventDateTime <= E1.EventDateTime
    )
Select SectionId, TagEventDateTime
From TaggedData
Group By SectionId, TagEventDateTime

整个日期的SQL差异

1 个答案: