SQL Date and Time

Determine whether the date is equal:Select datediff (D, '2014-9-2 ', '2014-9-2 ')0 is the same
Within a certain period of time: (datediff (D, from_date, '2017-9-8 ')> = 0 and datediff (D, '2017-9-8', to_date)> = 0)
The default datetime format of the Chinese version of SQL Server is yyyy-mm-dd thh: mm: Ss. Mmm.
Example: Select getdate () 11:06:08. 177
Frequently Used date format conversion methods:
Select convert (varchar, getdate (), 120)
11:06:08

Select convert (varchar (12), getdate (), 111)
2004/09/12

Select convert (varchar (12), getdate (), 112)
20040912

Select convert (varchar (12), getdate (), 102)
2004.09.12

Select convert (varchar (12), getdate (), 101)
09/12/2004

Select convert (varchar (12), getdate (), 103)
12/09/2004

Select convert (varchar (12), getdate (), 104)
12.09.2004

Select convert (varchar (12), getdate (), 105)
12-09-2004

Select convert (varchar (12), getdate (), 106)
12 09 2004

Select convert (varchar (12), getdate (), 107)
09 12,200 4

Select convert (varchar (12), getdate (), 108)
11:06:08

Select convert (varchar (12), getdate (), 109)
09 12, 2004 1

Select convert (varchar (12), getdate (), 110)
09-12-2004

Select convert (varchar (12), getdate (), 113)
12 09 2004 1

Select convert (varchar (12), getdate (), 114)
11:06:08. 177