Question

我有以下声明

select pkid 
from AttendancePosting 
where datename(dw,AttDate) = 'Sunday' and empid=4 and attdate='2015-12-13' 
group by PKId,timeout
--having 9=9
having cast(sum((datepart(minute, timeout)))/2 as float )+''=cast(datepart(minute,timeout) as float) +''

问题是

having cast(sum((datepart(minute, timeout)))/2 as float )+''=cast(datepart(minute,timeout) as float) +''

不工作。 cast(sum((datepart(minute, timeout)))/2 as float )和cast(datepart(minute,timeout) as float)都带来相同的值，但select语句仍未获取任何记录，两者都返回9

我已经像这样检查了它

select pkid 
from AttendancePosting 
where datename(dw,AttDate) = 'Sunday' and empid=4 and attdate='2015-12-13' 
group by PKId,timeout
having 9=9

它带来的记录，任何帮助将不胜感激。

Answer 1

首先，您的语句datepart(minute, timeout)/2将返回一个整数。您可以通过更精确地使SQL Server变得更加精确datepart(minute, timeout)/2.。

其次，浮点数是近似值。您最好使用ROUND()并指定您认为合适的小数位数。例如：round(sum((datepart(minute, timeout)))/2.0, 3)。

条款没有按预期工作

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