| title | description | author | ms.author | ms.reviewer | ms.date | ms.service | ms.subservice | ms.topic | f1_keywords | helpviewer_keywords | dev_langs | monikerRange | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
DATEDIFF (Transact-SQL) | Transact-SQL reference for the DATEDIFF function. Returns the numerical difference between a start and end date based on datepart. | markingmyname | maghan | randolphwest | 10/26/2024 | sql | t-sql | reference |
|
|
| >=aps-pdw-2016 || =azuresqldb-current || =azure-sqldw-latest || >=sql-server-2016 || >=sql-server-linux-2017 || =azuresqldb-mi-current |
[!INCLUDE sql-asdb-asdbmi-asa-pdw]
This function returns the count (as a signed integer value) of the specified datepart boundaries crossed between the specified startdate and enddate.
See DATEDIFF_BIG for a function that handles larger differences between the startdate and enddate values. See Date and time data types and functions for an overview of all [!INCLUDE tsql] date and time data types and functions.
:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: Transact-SQL syntax conventions
DATEDIFF ( datepart , startdate , enddate ) Specifies the units in which DATEDIFF reports the difference between the startdate and enddate. Commonly used datepart units include month or second.
The datepart value can't be specified in a variable, nor as a quoted string like 'month'.
The following table lists all the valid datepart values. DATEDIFF accepts either the full name of the datepart, or any listed abbreviation of the full name.
| datepart name | 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 |
Each specific datepart name and abbreviations for that datepart name returns the same value.
An expression that can resolve to one of the following values:
- date
- datetime
- datetimeoffset
- datetime2
- smalldatetime
- time
Use four-digit years to avoid ambiguity. See Server configuration: two digit year cutoff for information about two-digit year values.
See startdate.
int
The int difference between the startdate and enddate, expressed in the boundary set by datepart.
For example, SELECT DATEDIFF(day, '2036-03-01', '2036-02-28'); returns -2, hinting that 2036 must be a leap year. This case means that if we start at startdate2036-03-01, and then count -2 days, we reach the enddate of 2036-02-28.
For a return value out of range for int (-2,147,483,648 to +2,147,483,647), DATEDIFF returns an error. For millisecond, the maximum difference between startdate and enddate is 24 days, 20 hours, 31 minutes, and 23.647 seconds. For second, the maximum difference is 68 years, 19 days, 3 hours, 14 minutes, and 7 seconds.
If startdate and enddate are both assigned only a time value, and the datepart isn't a time datepart, DATEDIFF returns 0.
DATEDIFF uses the time zone offset component of startdate or enddate to calculate the return value.
Because smalldatetime is accurate only to the minute, seconds and milliseconds are always set to 0 in the return value when startdate or enddate have a smalldatetime value.
If only a time value is assigned to a date data type variable, DATEDIFF sets the value of the missing date part to the default value: 1900-01-01. If only a date value is assigned to a variable of a time or date data type, DATEDIFF sets the value of the missing time part to the default value: 00:00:00. If either startdate or enddate have only a time part and the other only a date part, DATEDIFF sets the missing time and date parts to the default values.
If startdate and enddate have different date data types, and one has more time parts or fractional seconds precision than the other, DATEDIFF sets the missing parts of the other to 0.
The following statements have the same startdate and the same enddate values. Those dates are adjacent and they differ in time by a hundred nanoseconds (.0000001 second). The difference between the startdate and enddate in each statement crosses one calendar or time boundary of its datepart. Each statement returns 1.
SELECT DATEDIFF(year, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(quarter, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(month, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(dayofyear, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(day, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(week, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(weekday, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(hour, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(minute, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(second, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(millisecond, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000'); SELECT DATEDIFF(microsecond, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');If startdate and enddate have different year values, but they have the same calendar week values, DATEDIFF returns 0 for datepartweek.
Use DATEDIFF in the SELECT <list>, WHERE, HAVING, GROUP BY, and ORDER BY clauses.
DATEDIFF implicitly casts string literals as a datetime2 type. In other words, DATEDIFF doesn't support the format YDM when the date is passed as a string. You must explicitly cast the string to a datetime or smalldatetime type to use the YDM format.
Specifying SET DATEFIRST has no effect on DATEDIFF. DATEDIFF always uses Sunday as the first day of the week to ensure the function operates in a deterministic way.
DATEDIFF might overflow with a precision of minute or higher, if the difference between enddate and startdate returns a value that is out of range for int.
[!INCLUDE article-uses-adventureworks]
These examples use different types of expressions as arguments for the startdate and enddate parameters.
This example calculates the number of day boundaries crossed between dates in two columns in a table.
CREATETABLEdbo.Duration ( startDate DATETIME2, endDate DATETIME2 ); INSERT INTOdbo.Duration (startDate, endDate) VALUES ('2007-05-06 12:10:09', '2007-05-07 12:10:09'); SELECT DATEDIFF(day, startDate, endDate) AS [Duration] FROMdbo.Duration;[!INCLUDE ssresult-md]
Duration -------- 1 In this example, user-defined variables serve as arguments for startdate and enddate.
DECLARE @startdate AS DATETIME2 ='2007-05-05 12:10:09.3312722'; DECLARE @enddate AS DATETIME2 ='2007-05-04 12:10:09.3312722'; SELECT DATEDIFF(day, @startdate, @enddate);This example uses scalar system functions as arguments for startdate and enddate.
SELECT DATEDIFF(millisecond, GETDATE(), SYSDATETIME());This example uses scalar subqueries and scalar functions as arguments for startdate and enddate.
USE AdventureWorks2022; GO SELECT DATEDIFF(day, (SELECTMIN(OrderDate) FROMSales.SalesOrderHeader), (SELECTMAX(OrderDate) FROMSales.SalesOrderHeader));This example uses character constants as arguments for startdate and enddate.
SELECT DATEDIFF(day, '2007-05-07 09:53:01.0376635', '2007-05-08 09:53:01.0376635');This example uses a numeric expression, (GETDATE() + 1), and scalar system functions GETDATE and SYSDATETIME, as arguments for enddate.
USE AdventureWorks2022; GO SELECT DATEDIFF(day, '2007-05-07 09:53:01.0376635', GETDATE() +1) AS NumberOfDays FROMSales.SalesOrderHeader; GO USE AdventureWorks2022; GO SELECT DATEDIFF(day, '2007-05-07 09:53:01.0376635', DATEADD(day, 1, SYSDATETIME())) AS NumberOfDays FROMSales.SalesOrderHeader; GOThis example uses a ranking function as an argument for startdate.
USE AdventureWorks2022; GO SELECTp.FirstName, p.LastName, DATEDIFF(day, ROW_NUMBER() OVER (ORDER BYa.PostalCode), SYSDATETIME()) AS'Row Number'FROMSales.SalesPersonAS s INNER JOINPerson.PersonAS p ONs.BusinessEntityID=p.BusinessEntityIDINNER JOINPerson.AddressAS a ONa.AddressID=p.BusinessEntityIDWHERE TerritoryID IS NOT NULLAND SalesYTD <>0;This example uses an aggregate window function as an argument for startdate.
USE AdventureWorks2022; GO SELECTsoh.SalesOrderID, sod.ProductID, sod.OrderQty, soh.OrderDate, DATEDIFF(day, MIN(soh.OrderDate) OVER (PARTITION BY soh.SalesOrderID), SYSDATETIME()) AS'Total'FROMSales.SalesOrderDetailAS sod INNER JOINSales.SalesOrderHeaderAS soh ONsod.SalesOrderID=soh.SalesOrderIDWHEREsoh.SalesOrderIDIN (43659, 58918); GO-- DOES NOT ACCOUNT FOR LEAP YEARS DECLARE @date1 AS DATETIME, @date2 AS DATETIME, @result ASVARCHAR (100); DECLARE @years ASINT, @months ASINT, @days ASINT, @hours ASINT, @minutes ASINT, @seconds ASINT, @milliseconds ASINT; SET @date1 ='1900-01-01 00:00:00.000'; SET @date2 ='2018-12-12 07:08:01.123'; SELECT @years = DATEDIFF(yy, @date1, @date2); IF DATEADD(yy, -@years, @date2) < @date1 SELECT @years = @years -1; SET @date2 = DATEADD(yy, -@years, @date2); SELECT @months = DATEDIFF(mm, @date1, @date2); IF DATEADD(mm, -@months, @date2) < @date1 SELECT @months = @months -1; SET @date2 = DATEADD(mm, -@months, @date2); SELECT @days = DATEDIFF(dd, @date1, @date2); IF DATEADD(dd, -@days, @date2) < @date1 SELECT @days = @days -1; SET @date2 = DATEADD(dd, -@days, @date2); SELECT @hours = DATEDIFF(hh, @date1, @date2); IF DATEADD(hh, -@hours, @date2) < @date1 SELECT @hours = @hours -1; SET @date2 = DATEADD(hh, -@hours, @date2); SELECT @minutes = DATEDIFF(mi, @date1, @date2); IF DATEADD(mi, -@minutes, @date2) < @date1 SELECT @minutes = @minutes -1; SET @date2 = DATEADD(mi, -@minutes, @date2); SELECT @seconds = DATEDIFF(s, @date1, @date2); IF DATEADD(s, -@seconds, @date2) < @date1 SELECT @seconds = @seconds -1; SET @date2 = DATEADD(s, -@seconds, @date2); SELECT @milliseconds = DATEDIFF(ms, @date1, @date2); SELECT @result = ISNULL(CAST (NULLIF (@years, 0) ASVARCHAR (10)) +' years,', '') + ISNULL(''+ CAST (NULLIF (@months, 0) ASVARCHAR (10)) +' months,', '') + ISNULL(''+ CAST (NULLIF (@days, 0) ASVARCHAR (10)) +' days,', '') + ISNULL(''+ CAST (NULLIF (@hours, 0) ASVARCHAR (10)) +' hours,', '') + ISNULL(''+ CAST (@minutes ASVARCHAR (10)) +' minutes and', '') + ISNULL(''+ CAST (@seconds ASVARCHAR (10)) + CASE WHEN @milliseconds >0 THEN '.'+ CAST (@milliseconds ASVARCHAR (10)) ELSE '' END +' seconds', ''); SELECT @result;[!INCLUDE ssResult]
118 years, 11 months, 11 days, 7 hours, 8 minutes and 1.123 seconds Examples: [!INCLUDE ssazuresynapse-md] and [!INCLUDE ssPDW]
These examples use different types of expressions as arguments for the startdate and enddate parameters.
This example calculates the number of day boundaries crossed between dates in two columns in a table.
CREATETABLEdbo.Duration ( startDate DATETIME2, endDate DATETIME2 ); INSERT INTOdbo.Duration (startDate, endDate) VALUES ('2007-05-06 12:10:09', '2007-05-07 12:10:09'); SELECT TOP (1) DATEDIFF(day, startDate, endDate) AS [Duration] FROMdbo.Duration;Duration -------- 1 This example uses scalar subqueries and scalar functions as arguments for startdate and enddate.
-- Uses AdventureWorksSELECT TOP (1) DATEDIFF(day, (SELECTMIN(HireDate) FROMdbo.DimEmployee), (SELECTMAX(HireDate) FROMdbo.DimEmployee)) FROMdbo.DimEmployee;This example uses character constants as arguments for startdate and enddate.
-- Uses AdventureWorksSELECT TOP (1) DATEDIFF(day, '2007-05-07 09:53:01.0376635', '2007-05-08 09:53:01.0376635') FROM DimCustomer;This example uses a ranking function as an argument for startdate.
-- Uses AdventureWorksSELECT FirstName, LastName, DATEDIFF(day, ROW_NUMBER() OVER (ORDER BY DepartmentName), SYSDATETIME()) AS RowNumber FROMdbo.DimEmployee;This example uses an aggregate window function as an argument for startdate.
-- Uses AdventureWorksSELECT FirstName, LastName, DepartmentName, DATEDIFF(year, MAX(HireDate) OVER (PARTITION BY DepartmentName), SYSDATETIME()) AS SomeValue FROMdbo.DimEmployee;