DATEDIFF function in SQL Server

This article will show you in detail how to use SQL Server's datetime DATEDIFF () function with syntax and specific examples to make it easier to visualize and capture functions.

Describe

The DATEDIFF function in SQL Server returns the difference between two time values ​​based on the specified time period. Two time values ​​must be dates or date and time expressions.

Syntax

To use the DATEDIFF function in SQL Server, we use the following syntax:

 DATEDIFF(dangthoigian, thoigian1, thoigian2) 

Parameters :

1. dangthoigian: the type of time used to calculate the difference between thoigian1 and thoigian2. It may be one of the following values:
   Value Explanation year, yyyy, yy Yearquarter, qq, qQuýmonth, mm, mThdaydayofyearDate in daysday, dy, yYdayweek, ww, wkTuwwdayday, dw, w Day of the day, hhGinminute, mi, nPhútsecond, ss, s Millisecond, msMis second
2. thoigian1, thoigian2: time interval for calculating the difference.

Note :

1. DATEDIFF can be used in later versions of SQL Server: SQL Server 2017, SQL Server 2016, SQL Server 2014, SQL Server 2012, SQL Server 2008 R2, SQL Server 2008, and SQL Server 2005.

For example

Take a look and explore some examples of DATEDIFF functions in SQL Server.

 SELECT DATEDIFF(year, '2019/04/28', '2021/04/28'); 
 Result: 2 
 
 SELECT DATEDIFF(yyyy, '2019/04/28', '2021/04/28'); 
 Result: 2 
 
 SELECT DATEDIFF(yy, '2019/04/28', '2021/04/28'); 
 Result: 2 
 
 SELECT DATEDIFF(month, '2019/01/01', '2019/04/28'); 
 Result: 3 
 
 SELECT DATEDIFF(day, '2019/01/01', '2019/04/28'); 
 Result: 117 
 
 SELECT DATEDIFF(hour, '2019/04/28 08:00', '2019/04/28 10:45'); 
 Result: 2 
 
 SELECT DATEDIFF(minute, '2019/04/28 08:00', '2019/04/28 10:45'); 
 Result: 165 

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