Adventures in Machine Learning

Extracting Weekday Names from Dates in SQL Server: Two Methods

Extracting Day of the Week from a Date in SQL Server

Have you ever needed to extract the day of the week from a date in SQL Server? Sometimes you may need this information to calculate certain metrics or to display it to the user.

In this article, we will explore two methods of extracting the day of the week: using the DATENAME() function and the FORMAT() function.

Using DATENAME() function

The DATENAME() function is a SQL Server built-in function that returns a string representing the specified datepart of the given date. One of the options for datepart is weekday (abbreviated as dw or w) which returns an integer value representing the day of the week (1 for Sunday, 2 for Monday, and so on).

You can use the weekday value to determine the day name as well. For example, to extract the day of the week and the day name from a date, you can use the following query:

SELECT DATENAME(dw, ‘2021-09-22’) as weekday_name, DATENAME(weekday, ‘2021-09-22’) as weekday_number

This will return:

weekday_name weekday_number

Wednesday 4

You can also use the weekday number to get the day name using the DATENAME() function. For example:

SELECT DATENAME(weekday, DATEADD(day, 2, ‘2021-09-20’)) as weekday_name

This will return:

weekday_name

Wednesday

Using FORMAT() function

The FORMAT() function is another built-in function in SQL Server that lets you format a date in a particular way. You can use it to extract the day name from a date by using the dddd or ddd format specifier.

For example, to extract the day name from a date, you can use the following query:

SELECT FORMAT(‘2021-09-22’, ‘dddd’) as weekday_name

This will return:

weekday_name

Wednesday

You can also use the shortened version of the format specifier ddd which will give you the abbreviated day name (e.g., Mon, Tue, Wed, etc.). SELECT FORMAT(‘2021-09-22’, ‘ddd’) as weekday_name

This will return:

weekday_name

Wed

Extracting Weekday Name in a Different Language

If you need to extract the weekday name in a different language, you can use the FORMAT() function with the locale argument.

Using FORMAT() function with Locale Argument

The locale argument in the FORMAT() function lets you specify the culture or language to use when formatting the date. You can use the CultureInfo class in .NET to get the appropriate culture object for the language you want.

For example, to extract the weekday name in French, you can use the following query:

SELECT FORMAT(‘2021-09-22’, ‘dddd’, ‘fr-FR’) as weekday_name

This will return:

weekday_name

mercredi

Example of Extracting Weekday Name in German

Let’s say you want to extract the weekday name in German. You can use the culture identifier de-DE for German (Germany).

SELECT FORMAT(‘2021-09-22’, ‘dddd’, ‘de-DE’) as weekday_name

This will return:

weekday_name

Mittwoch

Conclusion

In this article, we explored two methods of extracting the day of the week from a date in SQL Server: using the DATENAME() function and the FORMAT() function. We also saw how to extract the weekday name in a different language using the FORMAT() function with the locale argument.

I hope this article has been useful in helping you extract the weekday name from a date in SQL Server. In this article, we’ve covered two methods of extracting the day of the week from a date in SQL Server: using the DATENAME() function and the FORMAT() function.

We’ve also seen how to extract the weekday name in a different language using the FORMAT() function with the locale argument. It’s important to be able to extract this information for various reasons, and both methods are simple and easy to use.

By understanding these techniques, you can ensure that your SQL Server queries are accurate and useful. Always remember to choose the right method based on your needs and resources.

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