Dateadd function syntax and example in sql server?

Syntax

DATEADD(datepart,number,date)

Where date is a valid date expression and number is the number of interval you want to add. The number can either be positive, for dates in the future, or negative, for dates in the past.

datepart can be one of the following:

datepart	Abbreviation
year	yy, yyyy
quarter	qq, q
month	mm, m
dayofyear	dy, y
day	dd, d
week	wk, ww
weekday	dw, w
hour	hh
minute	mi, n
second	ss, s
millisecond	ms
microsecond	mcs
nanosecond	ns

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Example

Assume we have the following "Orders" table:

OrderId	ProductName	OrderDate
1	Jarlsberg Cheese	2008-11-11 13:23:44.657

Now we want to add 45 days to the "OrderDate", to find the payment date.

We use the following SELECT statement:

SELECT OrderId,DATEADD(day,45,OrderDate) AS OrderPayDate
FROM Orders

Result:

OrderId	OrderPayDate
1	2008-12-26 13:23:44.657