Sql как найти разницу между двумя датами

DATEDIFF (Transact-SQL)

[!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 (Transact-SQL) for a function that handles larger differences between the startdate and enddate values. See Date and Time Data Types and Functions (Transact-SQL) for an overview of all [!INCLUDEtsql] date and time data types and functions.

:::image type=»icon» source=»../../includes/media/topic-link-icon.svg» border=»false»::: Transact-SQL syntax conventions

Syntax

DATEDIFF ( datepart , startdate , enddate )  

[!INCLUDEsql-server-tsql-previous-offline-documentation]

Arguments

datepart
The units in which DATEDIFF reports the difference between the startdate and enddate. Commonly used datepart units include month or second.

The datepart value cannot 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.

[!NOTE]
Each specific datepart name and abbreviations for that datepart name will return the same value.

startdate
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 Configure the two digit year cutoff Server Configuration Option for information about two-digit year values.

enddate
See startdate.

Return Type

int

Return Value

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 startdate ‘2036-03-01’, 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 is not 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.

datepart boundaries

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(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 will return 0 for datepart week.

Remarks

Use DATEDIFF in the SELECT <list>, WHERE, HAVING, GROUP BY and ORDER BY clauses.

DATEDIFF implicitly casts string literals as a datetime2 type. This means that DATEDIFF does not 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 may 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.

Examples

These examples use different types of expressions as arguments for the startdate and enddate parameters.

A. Specifying columns for startdate and enddate

This example calculates the number of day boundaries crossed between dates in two columns in a table.

CREATE TABLE dbo.Duration  
    (startDate datetime2, endDate datetime2);  
    
INSERT INTO dbo.Duration(startDate, endDate)  
    VALUES ('2007-05-06 12:10:09', '2007-05-07 12:10:09');  
    
SELECT DATEDIFF(day, startDate, endDate) AS 'Duration'  
    FROM dbo.Duration;  
-- Returns: 1  

B. Specifying user-defined variables for startdate and enddate

In this example, user-defined variables serve as arguments for startdate and enddate.

DECLARE @startdate DATETIME2 = '2007-05-05 12:10:09.3312722';  
DECLARE @enddate   DATETIME2 = '2007-05-04 12:10:09.3312722';   
SELECT DATEDIFF(day, @startdate, @enddate);  

C. Specifying scalar system functions for startdate and enddate

This example uses scalar system functions as arguments for startdate and enddate.

SELECT DATEDIFF(millisecond, GETDATE(), SYSDATETIME());  

D. Specifying scalar subqueries and scalar functions for startdate and enddate

This example uses scalar subqueries and scalar functions as arguments for startdate and enddate.

USE AdventureWorks2012;  
GO  
SELECT DATEDIFF(day,
    (SELECT MIN(OrderDate) FROM Sales.SalesOrderHeader),  
    (SELECT MAX(OrderDate) FROM Sales.SalesOrderHeader));  

E. Specifying constants for startdate and enddate

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');  

F. Specifying numeric expressions and scalar system functions for enddate

This example uses a numeric expression, (GETDATE() + 1), and scalar system functions GETDATE and SYSDATETIME, as arguments for enddate.

USE AdventureWorks2012;  
GO  
SELECT DATEDIFF(day, '2007-05-07 09:53:01.0376635', GETDATE() + 1)
    AS NumberOfDays  
    FROM Sales.SalesOrderHeader;  
GO  
USE AdventureWorks2012;  
GO  
SELECT
    DATEDIFF(
            day,
            '2007-05-07 09:53:01.0376635',
            DATEADD(day, 1, SYSDATETIME())
        ) AS NumberOfDays  
    FROM Sales.SalesOrderHeader;  
GO  

G. Specifying ranking functions for startdate

This example uses a ranking function as an argument for startdate.

USE AdventureWorks2012;  
GO  
SELECT p.FirstName, p.LastName  
    ,DATEDIFF(day, ROW_NUMBER() OVER (ORDER BY   
        a.PostalCode), SYSDATETIME()) AS 'Row Number'  
FROM Sales.SalesPerson s   
    INNER JOIN Person.Person p   
        ON s.BusinessEntityID = p.BusinessEntityID  
    INNER JOIN Person.Address a   
        ON a.AddressID = p.BusinessEntityID  
WHERE TerritoryID IS NOT NULL   
    AND SalesYTD <> 0;  

H. Specifying an aggregate window function for startdate

This example uses an aggregate window function as an argument for startdate.

USE AdventureWorks2012;  
GO  
SELECT soh.SalesOrderID, sod.ProductID, sod.OrderQty, soh.OrderDate,
    DATEDIFF(day, MIN(soh.OrderDate)   
        OVER(PARTITION BY soh.SalesOrderID), SYSDATETIME()) AS 'Total'  
FROM Sales.SalesOrderDetail sod  
    INNER JOIN Sales.SalesOrderHeader soh  
        ON sod.SalesOrderID = soh.SalesOrderID  
WHERE soh.SalesOrderID IN(43659, 58918);  
GO  

I. Finding difference between startdate and enddate as date parts strings

-- DOES NOT ACCOUNT FOR LEAP YEARS
DECLARE @date1 DATETIME, @date2 DATETIME, @result VARCHAR(100);
DECLARE @years INT, @months INT, @days INT,
    @hours INT, @minutes INT, @seconds INT, @milliseconds INT;

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) AS VARCHAR(10)) + ' years,','')
     + ISNULL(' ' + CAST(NULLIF(@months,0) AS VARCHAR(10)) + ' months,','')    
     + ISNULL(' ' + CAST(NULLIF(@days,0) AS VARCHAR(10)) + ' days,','')
     + ISNULL(' ' + CAST(NULLIF(@hours,0) AS VARCHAR(10)) + ' hours,','')
     + ISNULL(' ' + CAST(@minutes AS VARCHAR(10)) + ' minutes and','')
     + ISNULL(' ' + CAST(@seconds AS VARCHAR(10)) 
     + CASE
            WHEN @milliseconds > 0
                THEN '.' + CAST(@milliseconds AS VARCHAR(10)) 
            ELSE ''
       END 
     + ' seconds','')

SELECT @result

[!INCLUDEssResult]

118 years, 11 months, 11 days, 7 hours, 8 minutes and 1.123 seconds

Examples: [!INCLUDEssazuresynapse-md] and [!INCLUDEssPDW]

These examples use different types of expressions as arguments for the startdate and enddate parameters.

J. Specifying columns for startdate and enddate

This example calculates the number of day boundaries crossed between dates in two columns in a table.

CREATE TABLE dbo.Duration 
    (startDate datetime2, endDate datetime2);
    
INSERT INTO dbo.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  
    FROM dbo.Duration;  
-- Returns: 1  

K. Specifying scalar subqueries and scalar functions for startdate and enddate

This example uses scalar subqueries and scalar functions as arguments for startdate and enddate.

-- Uses AdventureWorks  
  
SELECT TOP(1) DATEDIFF(day, (SELECT MIN(HireDate) FROM dbo.DimEmployee),  
    (SELECT MAX(HireDate) FROM dbo.DimEmployee))   
FROM dbo.DimEmployee;  
  

L. Specifying constants for startdate and enddate

This example uses character constants as arguments for startdate and enddate.

-- Uses AdventureWorks  
  
SELECT TOP(1) DATEDIFF(day,
    '2007-05-07 09:53:01.0376635',
    '2007-05-08 09:53:01.0376635') FROM DimCustomer;  

M. Specifying ranking functions for startdate

This example uses a ranking function as an argument for startdate.

-- Uses AdventureWorks  
  
SELECT FirstName, LastName,
    DATEDIFF(day, ROW_NUMBER() OVER (ORDER BY   
        DepartmentName), SYSDATETIME()) AS RowNumber  
FROM dbo.DimEmployee;  

N. Specifying an aggregate window function for startdate

This example uses an aggregate window function as an argument for startdate.

-- Uses AdventureWorks  
  
SELECT FirstName, LastName, DepartmentName,
    DATEDIFF(year, MAX(HireDate)  
        OVER (PARTITION BY DepartmentName), SYSDATETIME()) AS SomeValue  
FROM dbo.DimEmployee  

See also

DATEDIFF_BIG (Transact-SQL)
CAST and CONVERT (Transact-SQL)