有挑战性的SQL语句

Question

datediff(second, dateField, baseDate)

Answer 1

distinct by : datediff(minute, dateField, baseDate) / 2

Answer 2

declare @tb table(dt datetime)
insert @tb
select '2005-10-01 10:51' union
select '2005-10-01 10:52' union
select '2005-10-01 10:57' union
select '2005-10-01 10:58'--查询
select *
from @tb t
where datediff(minute,t.dt,(select min(dt) from @tb where dt>t.dt))<2--结果
/*
dt                                                     
------------------------------------------------------ 
2005-10-01 10:51:00.000
2005-10-01 10:57:00.000(2 row(s) affected)
*/