Question

C#运行sql执行datediff作为条件时,提示SQL语句错误

string querydate = DateTime.Now.ToString().Trim();
string strCondition = " where datediff(Minute,InquiryDate," + querydate + ") < 5";
string strsql = "select sum(MinTruck_Number)+sum(MidTruck_Number)+sum(LargeTruck_Number)+sum(MinCar_Number)+sum(LargeCar_Number)+sum(Trailer_Number)+sum(OutsizeTruck_Number) as SumProduct from HourNumberTable " + strCondition + " group by HourSegment";

我在SQL测试的语句：
select sum(MinTruck_Number)+sum(MidTruck_Number)+sum(LargeTruck_Number)+sum(MinCar_Number)+sum(LargeCar_Number)+sum(Trailer_Number)+sum(OutsizeTruck_Number) as SumProduct from HourNumberTable where datediff(Minute,InquiryDate,getdate())<5 group by HourSegment order by HourSegment desc
正确的，返回结果了，但在C#里为什么错了？请高手指点下，我就这些分了，全给了

Answer 1

string strCondition = " where datediff(Minute,InquiryDate," + querydate + ") < 5";

需要改成
string strCondition = " where datediff(Minute,InquiryDate,cast('" + querydate + "' as datetime) ) < 5";

Answer 2

string strCondition = " where datediff(Minute,InquiryDate,'" + querydate + "') < 5";
要加单引号。