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Asked: 2026-05-11T08:18:48+00:00

I have a table that looks something like this CREATE TABLE MyTable( [RecordID] [bigint]

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I have a table that looks something like this

CREATE TABLE MyTable(     [RecordID] [bigint] IDENTITY(1,1) NOT NULL,     [PortName] [nvarchar](50) NULL,     [ReceivedEvent] [datetime] NULL,     [SentEvent] [datetime] NULL, );

The data could then be

   RecordID | PortName | ReceivedEvent       | SentEvent    1        | Port1    | 2009-10-20 10:20:00 | NULL    2        | Port2    | NULL                | 2009-10-20 10:10:00    3        | Port2    | NULL                | 2009-10-20 10:02:00    4        | Port2    | NULL                | 2009-10-20 11:00:00

I now need two question over this table:

1) I need to get a count of number of rows grouped by port and date (not time). The date is however a parameter in the question (In this case it could be ‘2009-10-20’). I also want the last ‘activity’ in each hour

   NumberOfRows | PortName | Hour | LastActivityInHour     2            | Port2    | 10   | 2009-10-20 10:10:00    1            | Port2    | 11   | 2009-10-20 11:00:00    1            | Port1    | 10   | 2009-10-20 10:20:00

2) I also need one question doing the same thing but grouped by day. And day is as I said a incoming parameter. In this case it could be ‘2009-10-20’

   NumberOfRows | PortName | LastActivityInDay     3            | Port2    | 2009-10-20 11:00:00    1            | Port1    | 2009-10-20 10:20:00
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1 Answer

  1. Since your data model is not properly normalized, this is uglier than it would need to be.

    SELECT   COUNT(t.RecordID) NumberOfRows,   t.PortName,   t.EventHour,   MAX(t.EventDateTime) LastActivityInHour FROM   (     SELECT       RecordID,       PortName,       COALESCE(ReceivedEvent, SentEvent) EventDateTime,       DATEPART(hh, COALESCE(ReceivedEvent, SentEvent)) EventHour,       DATEADD(dd, 0, DATEDIFF(dd, 0, COALESCE(ReceivedEvent, SentEvent))) EventDate     FROM       MyTable   ) t WHERE   t.EventDate = DATEADD(dd, 0, DATEDIFF(dd, 0, @TheDateInQuestion)) GROUP BY   t.PortName,   t.EventHour ORDER BY   t.PortName,   t.EventHour

    The SQL to do the by-date grouping is very similar, I’ll leave deriving it as an exercise for you. 😉

    I’m sure that there are other ways to get the same result. Making a view out of what is the inner query here will help clean up the query as a whole.

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