Calculate delay or difference between two dates in sql server

Calculate delay or difference between two dates in sql server

DATEDIFF (Transact-SQL)

DATEDIFF ( datepart , startdate , enddate )
You can use SQL Server DateDiff function to calculate difference between two dates. This delay can be calculated in days, months, years, minutes,hours or seconds.


Here is documentation from MSDN

datepart

Is the parameter that specifies on which part of the date to calculate the difference. The following table lists dateparts and abbreviations recognized by SQL Server 2005. These dateparts and abbreviations cannot be supplied as a user-declared variable.

Datepart	Abbreviations
year	yy, yyyy
quarter	qq, q
month	mm, m
dayofyear	dy, y
day	dd, d
week	wk, ww
Hour	hh
minute	mi, n
second	ss, s
millisecond	ms

startdate -

Is the starting date for the calculation. startdate is an expression that returns a datetime or smalldatetime value, or a character string in a date format.
Because smalldatetime is accurate only to the minute, when a smalldatetime value is used, seconds and milliseconds are always 0.
If you specify only the last two digits of the year, values less than or equal to the last two digits of the value of the two-digit year cutoff configuration option are in the same century as the cutoff year. Values greater than the last two digits of the value of this option are in the century that comes before the cutoff year. For example, if the two-digit year cutoff is 2049 (default), 49 is interpreted as 2049 and 2050 is interpreted as 1950. To avoid ambiguity, use four-digit years.
For more information about how to specify time values, see Time Formats. For more information about how to specify dates, see Date and Time (Transact-SQL).

enddate

Is the ending date for the calculation. enddate is an expression that returns a datetime or smalldatetime value, or a character string in a date format.

Return Types

integer

Examples

The following example determines the difference in days between the current date and the order date for products in the AdventureWorks database.

view sourceprint?

1.USE AdventureWorks;

2.GO

3.SELECT DATEDIFF(day, OrderDate, GETDATE()) AS NumberOfDays

4.FROM Sales.SalesOrderHeader;

5.GO