Everything Dev Needs to Know About SQL Server Dateadd

Hello Dev! Are you wondering how to manipulate date and time values in SQL Server? Look no further than the dateadd function! In this article, we will explore everything you need to know about dateadd and how to use it to its full potential. Let’s dive in!

What is SQL Server Dateadd?

Before we delve into the details of how to use dateadd, let’s first understand what it is. SQL Server dateadd is a built-in function that can add or subtract a specified time interval to a given date. The function returns a new datetime value that is based on the original datetime value and the provided interval. The syntax for the dateadd function is as follows:

For example, the following query adds 3 days to the current date:

SELECT DATEADD(day, 3, GETDATE()) AS NewDate;

The result of this query would be a new datetime value that is 3 days in the future from the current date.

Using SQL Server Dateadd for Common Tasks

Adding/Subtracting Years, Months and Days

The most common task that dateadd is used for is to add or subtract years, months or days from a given datetime value. This can be done by using the year, month or day datepart interval, respectively. For example:

SELECT DATEADD(year, 2, '2018-01-01') AS NewDate;

The result of this query would be a new datetime value that is 2 years in the future from the specified date (‘2020-01-01’). You can also subtract years, months or days by using a negative number:

SELECT DATEADD(month, -6, '2021-01-01') AS NewDate;

The result of this query would be a new datetime value that is 6 months in the past from the specified date (‘2020-07-01’).

Adding/Subtracting Hours, Minutes and Seconds

You can also use dateadd to add or subtract hours, minutes or seconds from a given datetime value. This can be done by using the hour, minute or second datepart interval, respectively. For example:

SELECT DATEADD(hour, 3, '2022-01-01 12:00:00') AS NewTime;

The result of this query would be a new datetime value that is 3 hours in the future from the specified time (‘2022-01-01 15:00:00’). You can also subtract hours, minutes or seconds by using a negative number:

SELECT DATEADD(second, -30, '2022-01-01 12:00:01') AS NewTime;

The result of this query would be a new datetime value that is 30 seconds in the past from the specified time (‘2022-01-01 12:00:31’).

Calculating the End of Month

One useful task that dateadd can be used for is to calculate the end of the month for a given datetime value. This can be done by using the month and day datepart intervals. For example:

SELECT DATEADD(day, -1, DATEADD(month, 1, '2022-02-01')) AS EndOfMonth;

The result of this query would be a new datetime value that represents the end of the month for the specified date (‘2022-02-28’).

FAQ

What is the maximum number of datepart intervals that can be added or subtracted?

The maximum number of datepart intervals that can be added or subtracted is 2,147,483,647. This is true for all datepart intervals except for milliseconds, microseconds and nanoseconds, which have a maximum value of 1000, 1000000 and 1000000000, respectively.

Can dateadd be used with datetimeoffset values?

Yes, dateadd can be used with datetimeoffset values in the same way that it is used with datetime values.

Is it possible to use dateadd to add/subtract business days?

No, dateadd does not have a built-in function for adding or subtracting business days (i.e., weekdays only). However, this can be achieved using a combination of dateadd and case statements. See the following article for an example: Calculating Workdays and Work Hours in SQL Server.

Can dateadd be used with non-datetime values?

No, dateadd can only be used with datetime values. If you need to add or subtract intervals from non-datetime values, you can use the dateadd function in combination with the cast or convert function.

Are there any limitations to using dateadd?

While dateadd is a powerful function for manipulating datetime values, it does have some limitations. For example, dateadd cannot be used to perform complex date calculations, such as determining the date of the third Thursday of a given month. In these cases, you may need to use a combination of dateadd and other functions, or create a user-defined function.

Are there any performance considerations when using dateadd?

Like any SQL Server function, there are performance considerations when using dateadd. In general, dateadd is a relatively fast and efficient function, but its performance can be impacted by the amount of data being processed and the complexity of the date calculations being performed. To optimize performance, it is important to write efficient queries and to use appropriate indexing.

Conclusion

We hope this article has provided you with a solid understanding of the SQL Server dateadd function and how to use it for a variety of common tasks. Remember to keep in mind the limitations and performance considerations when using dateadd, and to always test your code thoroughly before deploying it to a production environment. Good luck!