字符串转时间格式问题

Question

try:
convert(smalldatetime,substring('20040910',1,4)+'-'+substring('20040910',5,2)+'-'+substring('20040910',7,2))

Answer 1

cast('20040910' as smalldatetime)

Answer 2

select convert (smalldatetime ,convert(char(4),'20040729')+'-'
+substring('20040729',5,2)+'-'
+substring('20040729',7,2))

Answer 3

select convert(smalldatetime,'20040910',120)

Answer 4

declare @str char(10)
set @str=20040910
select cast(@str as smalldatetime)