Date Format in SQL Server

Hello Dev, as a developer, it’s important to understand the various date formats available in SQL Server. It can make a big difference in how you work with and manipulate dates in your database. This article will cover everything you need to know about date formats in SQL Server.

What is a Date Format?

A date format is a pattern that is used to display or interpret dates. In SQL Server, a date format determines how a date value is displayed or interpreted. Dates can be displayed in a variety of formats, depending on the format code used.

Common Date Formats in SQL Server

There are many different date formats that can be used in SQL Server. Some of the common ones include:

Date Format Code	Example	Description
MM/DD/YYYY	10/25/2021	Month/Day/Year
DD/MM/YYYY	25/10/2021	Day/Month/Year
YYYY-MM-DD	2021-10-25	Year-Month-Day
MMM DD, YYYY	Oct 25, 2021	Abbreviated Month Day, Year

These are just a few examples of the many different date formats available in SQL Server. It’s important to choose the right format for your needs to ensure that your date values are properly displayed, interpreted, and manipulated.

How to Set a Date Format in SQL Server

The default date format in SQL Server is determined by the language setting of the server. However, you can set a different date format for a specific query or session. To do this, you can use the SET DATEFORMAT statement followed by the desired date format code.

For example, if you wanted to set the date format to DD/MM/YYYY for a specific query, you would use the following statement:

SET DATEFORMAT dmy;

This would set the date format to Day/Month/Year for the duration of that query only.

Date Functions in SQL Server

In addition to understanding date formats, it’s important to know how to work with dates in SQL Server. One way to do this is through the use of date functions.

Common Date Functions in SQL Server

There are many different date functions that can be used in SQL Server. Some of the common ones include:

Function	Description
GETDATE()	Returns the current system date and time
DATEADD()	Adds or subtracts a specified time interval from a date
DATEDIFF()	Returns the difference between two dates in a specified time interval
YEAR()	Returns the year portion of a date
MONTH()	Returns the month portion of a date
DAY()	Returns the day portion of a date

These are just a few examples of the many different date functions available in SQL Server. Familiarizing yourself with these functions can make it much easier to work with and manipulate date values in your database.

Frequently Asked Questions

Q: How do I convert a string to a date in SQL Server?

A: You can use the CONVERT() function to convert a string to a date in SQL Server. For example, to convert a string in the format “MM/DD/YYYY” to a date, you could use the following statement:

CONVERT(date, '10/25/2021', 101)

The third argument (101) specifies the format code for the input string.

Q: How do I format a date as a string in SQL Server?

A: You can use the CONVERT() function to format a date as a string in SQL Server. For example, to format a date as “MMM DD, YYYY”, you could use the following statement:

CONVERT(varchar, GETDATE(), 107)

The third argument (107) specifies the format code for the output string.

Q: How do I perform calculations with dates in SQL Server?

A: You can use the various date functions in SQL Server, such as DATEADD() and DATEDIFF(), to perform calculations with dates. For example, to add 10 days to a date, you could use the following statement:

DATEADD(day, 10, GETDATE())

This would add 10 days to the current date and time.

Q: Can I store dates as strings in SQL Server?

A: While it is technically possible to store dates as strings in SQL Server, it is not recommended. Storing dates as strings can make it much more difficult to work with them and perform calculations. It’s best to store dates as their native date data type and format them as needed for display purposes.

Q: How do I find the difference between two dates in SQL Server?

A: You can use the DATEDIFF() function to find the difference between two dates in SQL Server. For example, to find the number of days between two dates, you could use the following statement:

DATEDIFF(day, '2021-10-25', '2021-11-10')

This would return the number of days between the two dates (16).

Conclusion

Understanding date formats and how to work with dates in SQL Server is an essential skill for any developer. By familiarizing yourself with the various date formats and functions available in SQL Server, you can ensure that your date values are properly displayed, interpreted, and manipulated. If you have any additional questions or need further assistance, don’t hesitate to reach out to the SQL Server community for help.