SQL从DateTime中减去时间

Question

I have two fields of data, 'CreatedDate' datetime (eg. 2013-11-06 1:00:00.000) and another is 'TimeToLive' time(7) (eg. 01:00:00)

I would like to check if the created date is more than an hour past the current time

I have tried DATEADD(hour, - (TimeToLive), GETDATE()); and various implementation doing a convert to datetime to get the adjusted datetime but no success overall

Answer 1

SELECT DATEADD(hour, -DATEPART(hour, TimeToLive), GETDATE());

如果需要，您可以展开以减去其他日期部分（分钟，秒）。

Answer 2

如果您使用的是Oracle，则可能需要签出NUMTODSINTERVAL功能。