• Here's my pseudo-code expanded a bit to accommodate the start and end date bits:

    declare @StartDate datetime

    ,@EndDate datetime

    set @EndDate = dateadd(hour, 8, DATEADD(dd, 0, DATEDIFF(dd, 0, DATEADD(HOUR, - 8, getdate()))))

    set @StartDate = dateadd(hour, - 73, @EndDate)

    select col1

    ,col2

    from table

    where [convert varchar date and time to datetime] between @StartDate

    and @EndDate

    That's how it works in T-SQL. Just need to convert that to Oracle.

    --Edit: fixed typo.

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