SQL Server Date Processing DateDiff

Grammar:

DATEDIFF (datepart,startdate,enddate)

The datepart parameter can be the following value:

Date-part:year | Quarter | Month | Week | Day | Hour | Minute | Second | Millisecond

The parameter date-part specifies the date portion of the interval to be measured.

DatePart	Abbreviations
Years	YY, yyyy
Quarter	QQ, Q
Month	MM, M
The day of the year	Dy, y
Day	DD, D
Week	WK, WW
Week	DW, W
Hours	hh
Minutes	MI, n
Seconds	SS, S
Milliseconds	Ms
Subtle	MCs
Na-Sec	Ns

e.g.:

Choose:

The following statement returns 1:select DateDiff (hour, ' 4:00AM ', ' 5:50am ')

The following statement returns 102:select DateDiff (month, ' 1987/05/02 ', ' 1995/11/15 ')

The following statement returns 0:select DateDiff (day, ' 00:00 ', ' 23:59 ')

The following statement returns 4:select DateDiff (day, ' 1999/07/19 00:00 ', ' 1999/07/23 23:59 ')

The following statement returns 0:select DateDiff (month, ' 1999/07/19 ', ' 1999/07/23 ')

The following statement returns 1:select DateDiff (month, ' 1999/07/19 ', ' 1999/08/23 ')

Conditional statements:

SELECT * from MyDate where DateDiff (Day,datetime, ' 2016/05/06 14:30:00 ') =0

SQL Server Date Processing DateDiff