Dateadd in SQL Server

Hello Dev, in this journal article, we will be exploring the Dateadd function in SQL Server. As you might know, SQL Server is a powerful database management system used by millions of businesses worldwide. Dateadd function is one of the most useful and widely used functions in SQL Server, and it can greatly simplify your work when dealing with time and date data. In this article, we will explain what Dateadd function is, how it works, and how to use it to perform various date and time calculations in SQL Server.

What is Dateadd Function?

The Dateadd function in SQL Server is a built-in function that is used to add a specified number of days, months, or years to a date value. The syntax for the Dateadd function is:

DATEADD(datepart, number, date)
datepart: specifies the part of the date to which the number will be added (day, month, year)
number: the number of units (days, months, years) to be added
date: the date to which the number of units will be added

For example, if we want to add five days to a date value, we can use the following query:

SELECT DATEADD(day, 5, '2022-03-15')

This query will output the date value ‘2022-03-20’, which is five days ahead of the original date value.

How Does Dateadd Function Work?

When you use the Dateadd function in SQL Server, the function takes the specified number of units (days, months, or years) and adds them to the specified datepart (day, month, or year) of the date value. The resulting date value is returned as the output of the function.

For example, if we want to add three months to a date value, the Dateadd function will take the original month of the date value, add three months to it, and then return the resulting date value. If the resulting date is invalid (for example, if adding three months to February 29th would result in an invalid date), the function will automatically adjust the date to the nearest valid date.

Using Dateadd Function in SQL Server

Now that we know what the Dateadd function is and how it works, let’s look at some practical examples of how to use it in SQL Server.

Adding Days to a Date

To add a specified number of days to a date value in SQL Server, we can use the following query:

SELECT DATEADD(day, 10, '2022-03-15')

This query will output the date value ‘2022-03-25’, which is ten days ahead of the original date value.

Adding Months to a Date

To add a specified number of months to a date value in SQL Server, we can use the following query:

SELECT DATEADD(month, 3, '2022-03-15')

This query will output the date value ‘2022-06-15’, which is three months ahead of the original date value.

Adding Years to a Date

To add a specified number of years to a date value in SQL Server, we can use the following query:

SELECT DATEADD(year, 2, '2022-03-15')

This query will output the date value ‘2024-03-15’, which is two years ahead of the original date value.

FAQ about Dateadd Function in SQL Server

Q1. Can we subtract days, months or years from a date using the Dateadd function?

Yes, we can subtract days, months, or years from a date value by passing a negative number as the second parameter of the Dateadd function. For example:

SELECT DATEADD(day, -5, '2022-03-15')

This query will output the date value ‘2022-03-10’, which is five days behind the original date value.

Q2. Can we add fractions of days, months, or years using the Dateadd function?

No, the Dateadd function only accepts integers as the second parameter. If you need to add fractions of days, months, or years to a date value, you will need to use other functions or calculations.

Q3. Can we use variables instead of literal values with the Dateadd function?

Yes, we can use variables instead of literal values with the Dateadd function. For example:

DECLARE @myDate datetime = '2022-03-15';DECLARE @daysToAdd int = 5;SELECT DATEADD(day, @daysToAdd, @myDate);

This query will output the date value ‘2022-03-20’, which is five days ahead of the original date value stored in the @myDate variable.

Conclusion

In conclusion, the Dateadd function in SQL Server is a powerful tool for performing various date and time calculations. It allows you to easily add or subtract days, months, or years to a date value, which can simplify your work and save you time. By understanding how the Dateadd function works and how to use it in different ways, you can improve your productivity and efficiency when working with date and time data in SQL Server.