Datepart SQL Server

Hello Dev, welcome to our journal article about Datepart SQL Server. In this article, we will discuss everything you need to know about Datepart in SQL Server, from the basics to the advanced level. We hope you will find this article informative and useful. Let’s get started!

Introduction to Datepart in SQL Server

Datepart is a function in SQL Server that extracts a specific part of a date or time value. It is used to manipulate and analyze date and time data stored in SQL Server. Datepart function returns an integer value that represents the specified part of the date or time value.

The syntax for Datepart function is as follows:

DATEPART(datepart, date)

The datepart argument is a string that represents the part of the date or time value that you want to extract. The date argument is the date or time value from which you want to extract the specific part. Here are some commonly used datepart arguments:

Datepart	Description
year	Extracts the year from the date
quarter	Extracts the quarter from the date
month	Extracts the month from the date
dayofyear	Extracts the day of the year from the date
day	Extracts the day from the date

Frequently Asked Questions

Q: Can I use Datepart function with datetime datatype?

A: Yes, you can use Datepart function with datetime datatype.

Q: What is the range of values that Datepart function can return?

A: The range of values that Datepart function can return depends on the datepart argument. For example, the year datepart can return values from 1753 to 9999.

Q: Can I use Datepart function with time datatype?

A: Yes, you can use Datepart function with time datatype.

Q: What is the difference between Datepart and Datename function?

A: Datepart function returns an integer value that represents the specified part of the date or time value, while Datename function returns a character string that represents the specified part of the date or time value.

Q: Can I use Datepart function with smalldatetime datatype?

A: Yes, you can use Datepart function with smalldatetime datatype.

Using Datepart Function in SQL Server

Now that you have a basic understanding of Datepart function, let’s see how to use it in SQL Server. In this section, we will discuss some common examples of using Datepart function.

Example 1: Extracting Year from a Date

To extract the year from a date, you can use the year datepart as follows:

SELECT DATEPART(year, '2022-01-01')

This will return the year value 2022 as an integer.

You can also use a column name instead of a date value:

SELECT DATEPART(year, hire_date) FROM employees

This will return the year value of the hire_date column for each row in the employees table.

Example 2: Extracting Month from a Date

To extract the month from a date, you can use the month datepart as follows:

SELECT DATEPART(month, '2022-01-01')

This will return the month value 1 as an integer.

You can also use a column name instead of a date value:

SELECT DATEPART(month, birth_date) FROM employees

This will return the month value of the birth_date column for each row in the employees table.

Example 3: Extracting Day from a Date

To extract the day from a date, you can use the day datepart as follows:

SELECT DATEPART(day, '2022-01-01')

This will return the day value 1 as an integer.

You can also use a column name instead of a date value:

SELECT DATEPART(day, hire_date) FROM employees

This will return the day value of the hire_date column for each row in the employees table.

Example 4: Extracting Quarter from a Date

To extract the quarter from a date, you can use the quarter datepart as follows:

SELECT DATEPART(quarter, '2022-01-01')

This will return the quarter value 1 as an integer.

You can also use a column name instead of a date value:

SELECT DATEPART(quarter, hire_date) FROM employees

This will return the quarter value of the hire_date column for each row in the employees table.

Example 5: Extracting Day of Year from a Date

To extract the day of year from a date, you can use the dayofyear datepart as follows:

SELECT DATEPART(dayofyear, '2022-01-01')

This will return the day of year value 1 as an integer.

You can also use a column name instead of a date value:

SELECT DATEPART(dayofyear, hire_date) FROM employees

This will return the day of year value of the hire_date column for each row in the employees table.

Advanced Usage of Datepart Function in SQL Server

Now that you have learned the basic usage of Datepart function, let’s see some advanced usage of this function.

Example 6: Calculating Age from a Date

You can use the Datepart function to calculate the age of a person from their birth date. The following query calculates the age of employees in the employees table:

SELECT DATEDIFF(year, birth_date, GETDATE()) - (CASE WHEN DATEPART(dayofyear, birth_date) > DATEPART(dayofyear, GETDATE()) THEN 1 ELSE 0 END) AS age FROM employees

The DATEDIFF function calculates the difference in years between the birth date and the current date. The CASE statement checks if the birth date has occurred in the current year. If the birth date has not occurred in the current year, then it subtracts 1 from the age.

Example 7: Calculating Fiscal Quarter from a Date

You can use the Datepart function to calculate the fiscal quarter from a date. The following query calculates the fiscal quarter of the hire date of employees in the employees table:

SELECT CASE WHEN DATEPART(month, hire_date) IN (1, 2, 3) THEN 'Q3' WHEN DATEPART(month, hire_date) IN (4, 5, 6) THEN 'Q4' WHEN DATEPART(month, hire_date) IN (7, 8, 9) THEN 'Q1' ELSE 'Q2' END AS fiscal_quarter FROM employees

The CASE statement checks the month of the hire date and assigns the corresponding fiscal quarter.

Conclusion

In conclusion, Datepart function is a powerful tool in SQL Server for manipulating and analyzing date and time data. In this article, we have covered the basics of Datepart function, along with some common and advanced examples. We hope you found this article informative and useful in your SQL Server development projects.