DATEADD (Transact-SQL)
Returns a specified date with the specified number interval (signed integer) added to a specified datepart of that date.
For an overview of all Transact-SQL date and time data types and functions, see Date and Time Data Types and Functions (Transact-SQL). For information and examples that are common to date and time data types and functions, see Using Date and Time Data.
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Syntax
DATEADD (datepart , number, date )
Arguments
datepart
Is the part of date to which an integernumber is added. The following table lists all valid datepart arguments. User-defined variable equivalents are not valid.datepart
Abbreviations
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
number
Is an expression that can be resolved to an int that is added to a datepart of date. User-defined variables are valid.If you specify a value with a decimal fraction, the fraction is truncated and not rounded.
date
Is an expression that can be resolved to a time, date, smalldatetime, datetime, datetime2, or datetimeoffset value. date can be an expression, column expression, user-defined variable, or string literal. If the expression is a string literal, it must resolve to a datetime. To avoid ambiguity, use four-digit years. For information about two-digit years, see two digit year cutoff Option.
Return Types
The return data type is the data type of the date argument, except for string literals.
The return data type for a string literal is datetime. An error will be raised if the string literal seconds scale is more than three positions (.nnn) or contains the time zone offset part.
Note
If string literals are not explicitly cast for the date parameter, then locals that use a day-month-year (dmy) date format may get incorrect results when DATEADD is used in conjunction with other date/time functions.
Returning a datetime2 type
DATEADD returns a datetime2 type when the date parameter is a datetime2 type. When using string literals for the date parameter, you must explicitly cast them to a datetime2 type for DATEADD to return a datetime2 type.
Return Value
datepart Argument
dayofyear, day, and weekday return the same value.
Each datepart and its abbreviations return the same value.
If datepart is month and the date month has more days than the return month and the date day does not exist in the return month, the last day of the return month is returned. For example, September has 30 days; therefore, the two following statements return 2006-09-30 00:00:00.000:
SELECT DATEADD(month, 1, '2006-08-30')
SELECT DATEADD(month, 1, '2006-08-31')
number Argument
The number argument cannot exceed the range of int. In the following statements, the argument for number exceeds the range of int by 1. The following error message is returned: "Arithmetic overflow error converting expression to data type int."
SELECT DATEADD(year,2147483648, '2006-07-31');
SELECT DATEADD(year,-2147483649, '2006-07-31');
date Argument
The date argument cannot be incremented to a value outside the range of its data type. In the following statements, the number value that is added to the date value exceeds the range of the date data type. The following error message is returned: "Adding a value to a 'datetime' column caused overflow."
SELECT DATEADD(year,2147483647, '2006-07-31');
SELECT DATEADD(year,-2147483647, '2006-07-31');
Return Values for a smalldatetime date and a second or Fractional Seconds datepart
The seconds part of a smalldatetime value is always 00. If date is smalldatetime, the following apply:
If datepart is second and number is between -30 and +29, no addition is performed.
If datepart is second and number is less than-30 or more than +29, addition is performed beginning at one minute.
If datepart is millisecond and number is between -30001 and +29998, no addition is performed.
If datepart is millisecond and number is less than -30001 or more than +29998, addition is performed beginning at one minute.
Remarks
DATEADD can be used in the SELECT <list>, WHERE, HAVING, GROUP BY and ORDER BY clauses.
Fractional Seconds Precision
Addition for a datepart of microsecond or nanosecond for date data types smalldatetime, date, and datetime is not allowed.
Milliseconds have a scale of 3 (.123). microseconds have a scale of 6 (.123456). nanoseconds have a scale of 9 (.123456789). The time, datetime2, and datetimeoffset data types have a maximum scale of 7 (.1234567). If datepart is nanosecond, number must be 100 before the fractional seconds of date increase. A number between 1 and 49 is rounded down to 0 and a number from 50 to 99 is rounded up to 100.
The following statements add a datepart of millisecond, microsecond, or nanosecond.
DECLARE @datetime2 datetime2 = '2007-01-01 13:10:10.1111111'
SELECT '1 millisecond' ,DATEADD(millisecond,1,@datetime2)
UNION ALL
SELECT '2 milliseconds', DATEADD(millisecond,2,@datetime2)
UNION ALL
SELECT '1 microsecond', DATEADD(microsecond,1,@datetime2)
UNION ALL
SELECT '2 microseconds', DATEADD(microsecond,2,@datetime2)
UNION ALL
SELECT '49 nanoseconds', DATEADD(nanosecond,49,@datetime2)
UNION ALL
SELECT '50 nanoseconds', DATEADD(nanosecond,50,@datetime2)
UNION ALL
SELECT '150 nanoseconds', DATEADD(nanosecond,150,@datetime2);
/*
Returns:
1 millisecond 2007-01-01 13:10:10.1121111
2 milliseconds 2007-01-01 13:10:10.1131111
1 microsecond 2007-01-01 13:10:10.1111121
2 microseconds 2007-01-01 13:10:10.1111131
49 nanoseconds 2007-01-01 13:10:10.1111111
50 nanoseconds 2007-01-01 13:10:10.1111112
150 nanoseconds 2007-01-01 13:10:10.1111113
*/
Time Zone Offset
Addition is not allowed for time zone offset.
Examples
A. Incrementing datepart by an interval of 1
Each of the following statements increments datepart by an interval of 1.
DECLARE @datetime2 datetime2 = '2007-01-01 13:10:10.1111111'
SELECT 'year', DATEADD(year,1,@datetime2)
UNION ALL
SELECT 'quarter',DATEADD(quarter,1,@datetime2)
UNION ALL
SELECT 'month',DATEADD(month,1,@datetime2)
UNION ALL
SELECT 'dayofyear',DATEADD(dayofyear,1,@datetime2)
UNION ALL
SELECT 'day',DATEADD(day,1,@datetime2)
UNION ALL
SELECT 'week',DATEADD(week,1,@datetime2)
UNION ALL
SELECT 'weekday',DATEADD(weekday,1,@datetime2)
UNION ALL
SELECT 'hour',DATEADD(hour,1,@datetime2)
UNION ALL
SELECT 'minute',DATEADD(minute,1,@datetime2)
UNION ALL
SELECT 'second',DATEADD(second,1,@datetime2)
UNION ALL
SELECT 'millisecond',DATEADD(millisecond,1,@datetime2)
UNION ALL
SELECT 'microsecond',DATEADD(microsecond,1,@datetime2)
UNION ALL
SELECT 'nanosecond',DATEADD(nanosecond,1,@datetime2);
/*
Year 2008-01-01 13:10:10.1111111
quarter 2007-04-01 13:10:10.1111111
month 2007-02-01 13:10:10.1111111
dayofyear 2007-01-02 13:10:10.1111111
day 2007-01-02 13:10:10.1111111
week 2007-01-08 13:10:10.1111111
weekday 2007-01-02 13:10:10.1111111
hour 2007-01-01 14:10:10.1111111
minute 2007-01-01 13:11:10.1111111
second 2007-01-01 13:10:11.1111111
millisecond 2007-01-01 13:10:10.1121111
microsecond 2007-01-01 13:10:10.1111121
nanosecond 2007-01-01 13:10:10.1111111
*/
B. Incrementing more than one level of datepart in one statement
Each of the following statements increments datepart by a number large enough to also increment the next higher datepart of date.
DECLARE @datetime2 datetime2;
SET @datetime2 = '2007-01-01 01:01:01.1111111';
--Statement Result
-------------------------------------------------------------------
SELECT DATEADD(quarter,4,@datetime2); --2008-01-01 01:01:01.110
SELECT DATEADD(month,13,@datetime2); --2008-02-01 01:01:01.110
SELECT DATEADD(dayofyear,365,@datetime2); --2008-01-01 01:01:01.110
SELECT DATEADD(day,365,@datetime2); --2008-01-01 01:01:01.110
SELECT DATEADD(week,5,@datetime2); --2007-02-05 01:01:01.110
SELECT DATEADD(weekday,31,@datetime2); --2007-02-01 01:01:01.110
SELECT DATEADD(hour,23,@datetime2); --2007-01-02 00:01:01.110
SELECT DATEADD(minute,59,@datetime2); --2007-01-01 02:00:01.110
SELECT DATEADD(second,59,@datetime2); --2007-01-01 01:02:00.110
SELECT DATEADD(millisecond,1,@datetime2); --2007-01-01 01:01:01.110
C. Using expressions as arguments for the number and date parameters
The following examples use different types of expressions as arguments for the number and date parameters.
Specifying column as date
The following example adds 2 days to each OrderDate to calculate a new PromisedShipDate.
USE AdventureWorks;
GO
SELECT SalesOrderID
,OrderDate
,DATEADD(day,2,OrderDate) AS PromisedShipDate
FROM Sales.SalesOrderHeader;
Specifying user-defined variables as number and date
The following example specifies user-defined variables as arguments for number and date.
DECLARE @days int;
DECLARE @datetime datetime;
SET @days = 365;
SET @datetime = '2000-01-01 01:01:01.111'; /* 2000 was a leap year */
SELECT DATEADD(day, @days, @datetime);
Specifying scalar system function as date
The following example specifies SYSDATETIME for date.
SELECT DATEADD(month, 1, SYSDATETIME());
Specifying scalar subqueries and scalar functions as number and date
The following example uses scalar subqueries and scalar functions, MAX(ModifiedDate), as arguments for number and date. (SELECT TOP 1 ContactID FROM Person.Contact) is an artificial argument for the number parameter to show how to select a number argument from a value list.
USE AdventureWorks;
GO
SELECT DATEADD(month,(SELECT TOP 1 ContactID FROM Person.Contact),
(SELECT MAX(ModifiedDate) FROM Person.Contact));
Specifying constants as number and date
The following example uses numeric and character constants as arguments for number and date.
SELECT DATEADD(minute, 1, '2007-05-07 09:53:01.0376635');
Specifying numeric expressions and scalar system functions as number and date
The following example uses a numeric expressions (-(10/2)), unary operators (-), an arithmetic operator (/), and scalar system functions (SYSDATETIME) as arguments for number and date.
SELECT DATEADD(month,-(10/2), SYSDATETIME());
Specifying ranking functions as number
The following example uses a ranking function as arguments for number.
USE AdventureWorks;
GO
SELECT c.FirstName, c.LastName
,DATEADD(day,ROW_NUMBER() OVER (ORDER BY
a.PostalCode),SYSDATETIME()) AS 'Row Number'
FROM Sales.SalesPerson s
INNER JOIN Person.Contact c
ON s.SalesPersonID = c.ContactID
INNER JOIN Person.Address a
ON a.AddressID = c.ContactID
WHERE TerritoryID IS NOT NULL
AND SalesYTD <> 0;
Specifying an aggregate window function as number
The following example uses an aggregate window function as an argument for number.
USE AdventureWorks;
GO
SELECT SalesOrderID, ProductID, OrderQty
,DATEADD(day,SUM(OrderQty)
OVER(PARTITION BY SalesOrderID),SYSDATETIME()) AS 'Total'
FROM Sales.SalesOrderDetail
WHERE SalesOrderID IN(43659,43664);
GO
D. Using DATEADD for Locales that use the dmy date format
The following examples show how to use string literals with DATEADD for some locales.
Demonstrating the pitfalls of using an implicit cast of a string literal
The following example shows what happens when a string literal is not explicitly cast.
SET LANGUAGE Español;
GO
SELECT DATENAME(m, DATEADD(d, 0,'1987-03-07'));
SELECT DATENAME(m, '1987-03-07');
GO
The first select statement returns julio (July) for the month and the second select statement return marzo (March) for the month.
Avoiding erroneous results by explicitly casting the string literal
The following example shows how to explicitly cast the date parameter to avoid erroneous results.
SET LANGUAGE Español;
GO
SELECT DATENAME(m, DATEADD(d, 0, CAST('1987-03-07' AS datetime2)));
SELECT DATENAME(m, '1987-03-07');
GO
Both select statements return marzo (March) for the month.
Using a datetime2 variable in the place of a string literal
The following example avoids the direct use of a string literal.
SET LANGUAGE Español;
GO
DECLARE @d datetime2 = '1987-03-07';
SELECT DATENAME(m, DATEADD(d, 0, @d));
SELECT DATENAME(m, @d);
GO