The DATEDIFF function of SQL Server, a popular relational database management system, is among its most helpful features. This function computes the difference between two dates and can be applied in several ways to do intricate calculations and produce helpful results.

Introduction

The built-in SQL Server function known as DATEDIFF returns the difference between two dates in a given date part. It can be employed to determine how many days, weeks, months, or years between two dates. This function is especially helpful in business applications when it is important to figure out how many days there are between two dates, such as how many days there are between the date of the order and the date of delivery.

Syntax of DATEDIFF Function

DATEDIFF(datepart, startdate, enddate)

DATEDIFF Function Parameters

Three parameters are required for the DATEDIFF function:

Datepart

The section of the date that is used to determine the difference between the two dates is specified by the datepart parameter. The DATEDIFF function supports a number of date components, and each one has a unique formula for determining the difference.

• Year : calculates the number of years that have passed between the two dates.
• Quarter : calculates the number of quarters that have passed between the two dates.
• Month : calculates the number of months that have passed between the two dates.
• dayofyear: Based on a 365-day year, determines the number of days that separate the two dates.
• day: Determines how many days there are between the two dates.
• calculates the number of weeks that have passed between the two dates.
• calculates the time difference between the two dates in hours.
• calculates the time difference between the two dates in minutes.
• calculates the time difference between the two dates in seconds.
• calculates the time difference between the two dates in milliseconds.
• microsecond: Determines the number of microseconds that between the two dates.
• nanosecond: Determines the number of nanoseconds that separate the two dates.

Using DATEDIFF

Let’s explore some of the date parts that can be utilized with the DATEDIFF function in more detail.

Caculating the Year

SELECT DATEDIFF(Year, '2001-03-01', GETDATE())  as Year

Caculating the Month

SELECT DATEDIFF(MONTH, '2001-03-01', GETDATE())  as Months

Caculating the Days

SELECT DATEDIFF(DAY, '2001-03-01', GETDATE())  as Days

Caculating the Hours

SELECT DATEDIFF(HOUR, '2023-04-19 01:34:02', GETDATE())  as Hours

Caculating the Minutes

SELECT DATEDIFF(MINUTE, '2023-04-19 01:34:02', GETDATE())  as Minutes

Caculating the Seconds

SELECT DATEDIFF(SECOND, '2023-04-19 01:34:02', GETDATE())  as Seconds

Common DATEDIFF Errors

It’s crucial to be aware of certain typical mistakes that can happen while using the DATEDIFF function. The erroneous date portion being used is a frequent mistake. An error message will appear if you enter an invalid date portion. Make sure you are using a correct date part to fix this error.

Putting the startdate and enddate parameters in the wrong order is another frequent mistake. You will obtain a negative number if you reverse these parameters’ order. Make sure the startdate and enddate parameters are used in the right order to fix this issue.

Conclusion

The DATEDIFF function in SQL Server is a potent tool that can be used in a variety of ways to determine the difference between two dates. You can perform intricate calculations and provide useful reports by becoming an expert with this function. You may use the DATEDIFF function to its fullest extent and advance your knowledge of SQL programming with the knowledge and abilities you acquire from this tutorial.

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