一个蹊跷的SQL日期问题

Question

select 'diff'=datediff(dy,'2006-04-27','2006-04-08')
select 'diff'=datediff(dy,'2006-04-27','2006-05-01')
select 'diff'=datediff(dy,'2006-04-02','2006-04-08')
select 'diff'=datediff(dy,'2006-05-27','2006-04-08')
select 'diff'=datediff(dy,'2006-05-01','2006-04-27')

Answer 1

--这样？
select 'diff'=datediff(dy,'2006-04-27','2006-04-08')
select 'diff'=datediff(dy,'2006-04-27','2006-05-01')
select 'diff'=datediff(dy,'2006-04-02','2006-04-08')
select 'diff'=datediff(dy,'2006-05-27','2006-04-08')
select 'diff'=datediff(dy,'2006-05-01','2006-04-27')

Answer 2

select 'diff'=datediff(dy,2006-04-27,2006-04-08)
==
Select 'diff'=datediff(dy,2006-4-27,2006-4-8)
==
Select 'diff'=datediff(dy,1975,1994)!=
select 'diff'=datediff(dy,'2006-04-27','2006-04-08')

Answer 3

print convert(datetime, 2006-04-27)
print convert(datetime, 2006-04-08)
print convert(datetime,1)请lz尝试上面三句你代码里面所写的其实不是日期，而是从1900/01/01开始的天数。2006-4-27＝？