如何四舍五入一个SQL时间变量？

Question

我已经声明了一个值为23:59:59的时间变量。所以，我需要将它转到24:00。你有什么想法吗？

declare @t1 time = '23:59:59' 

这只在select语句中是必需的。我知道时间不能作为24:00插入。

http://msdn.microsoft.com/en-us/library/bb677243(v=sql.105).aspx

Answer 1

如何：

--setup 
    declare @t1 time = '23:59:59' 
    --declare @t1 time = '00:59:59' 
    --declare @t1 time = '00:59:29' 
    --declare @t1 time = '00:00:00' 

--solution for rounding to nearest hour 
    declare @temp1 int = datepart(minute, @t1)/30 
    set @temp1 = (DATEPART(hour, @t1) % 24) + @temp1 
    select @t1, cast(@temp1 as nvarchar(2)) + ':00' --not too worried about rpading hours since 1:00 makes sense 

--solution for rounding to nearest minute 
    declare @ss int = datepart(second, @t1)/30 
    , @mm int = datepart(minute, @t1) 
    , @hh int = datepart(hour, @t1) 
    , @oo nchar(2) = N'00' --used for padding 

    set @hh = (@hh + (@mm/30) * @ss) % 24 
    set @mm = (@mm + @ss) % 60 

    select @t1 
    , substring(@oo + cast(@hh as nvarchar(2)), case when @hh > 9 then 3 when @hh = 0 then 1 else 2 end, 2) --hours rpaded 
    + N':' 
    + substring(@oo + cast(@mm as nvarchar(2)), case when @mm > 9 then 3 when @mm = 0 then 1 else 2 end, 2) --minutes rpaded