计算给定小时内使用的分钟数

Question

给定开始和结束时间，我想知道给定小时内有多少分钟。

create function CalcMinsInHour(@start datetime, @end datetime, @hour int) 
returns int 
as 
begin 
    --Looking for best way to write this part 
end 

CalcMinsInHour('2012-01-18 8:15', '2012-01-18 10:30', 7) should return 0 
CalcMinsInHour('2012-01-18 8:15', '2012-01-18 10:30', 8) should return 45 
CalcMinsInHour('2012-01-18 8:15', '2012-01-18 10:30', 9) should return 60 
CalcMinsInHour('2012-01-18 8:15', '2012-01-18 10:30', 10) should return 30 
CalcMinsInHour('2012-01-18 8:15', '2012-01-18 10:30', 11) should return 0 

编辑：@Start和@End代表员工时钟进/出时间。所以是的，当他们在午夜工作时，他们可以跨越两天，但不会超过这一点。

Answer 1

这应该做的伎俩：

ALTER FUNCTION dbo.CalcMinsInHour(@start DATETIME, @end DATETIME, @hour INTEGER) 
RETURNS INTEGER 
AS 
BEGIN 
    DECLARE @StartOfHour DATETIME 
    DECLARE @EndOfHour DATETIME 
    SELECT @StartOfHour = DATEADD(hh, @hour, CAST(CAST(@start AS DATE) AS DATETIME)) 
    IF NOT (@StartOfHour BETWEEN @start and @end) 
     SET @StartOfHour = DATEADD(hh, @hour, CAST(CAST(@end AS DATE) AS DATETIME)) 

    SELECT @EndOfHour = DATEADD(hh, 1, @StartOfHour) 

RETURN 
(
SELECT 
    CASE WHEN @EndOfHour < @start OR @StartOfHour > @end THEN 0 ELSE 
     DATEDIFF(mi, 
      CASE WHEN @StartOfHour <= @start THEN @start ELSE @StartOfHour END, 
      CASE WHEN @EndOfHour > @end THEN @end ELSE @EndOfHour END) 
    END 
) 
END 

Answer 2

你可以使用DateDiff吗？

select DATEDIFF(Minute, '2011-11-10 00:00:59.900', '2011-11-10 00:01:00.100')

Answer 3

下面是计算的总分钟数（也可与多天）的功能：

create function CalcMinsInHour(@start datetime, @end datetime, @hour int) 
    returns int 
as 
begin 

    declare @selecterHourIntervals table (HourStart datetime, HourEnd datetime) 
    declare @currentDate datetime 

    /* start in the @start date, but the hour we want to count */ 
    set @currentDate = dateadd(hour, @hour, convert(datetime, convert(date, @start))) 

    /* for every day between @start-@end add out hour interval */ 
    while @currentDate <= @end 
    begin 
     insert into @selecterHourIntervals values (
         @currentDate, 
         dateadd(hour, 1, @currentDate)) 

     set @currentDate = dateadd(day, 1, @currentDate) 
    end 

    declare @totalMinutes int 

    /* for every hour interval in the table, select number of minutes 
     trimmed by the @start - @end interval and sum */ 
    select @totalMinutes = sum(DailyMinutes) 
    from 
     (select 
      datediff(minute, 
      case when HourStart > @start then HourStart else @start end, 
      case when HourEnd < @end then HourEnd else @end end) as DailyMinutes 
     from @selecterHourIntervals) TrimmedIntervals 
    where DailyMinutes > 0 

    return isnull(@totalMinutes, 0) 

end