Hello Dev! As a developer, you must be familiar with SQL Server and its various functions. In this article, we will discuss date functions in SQL Server, a topic that is important for any database developer or administrator. In this article, we will provide a comprehensive guide to these functions, including their syntax, usage, and examples. So, let’s get started!
Introduction to Date Functions in SQL Server
SQL Server provides various built-in functions that can be used to perform operations on dates and times. These functions can help you manipulate date and time values in different formats and perform various calculations as required. Some of the most commonly used date functions are:
- DATEPART
- DATEADD
- DATEDIFF
- GETDATE
- DATEFROMPARTS
DATEPART Function
The DATEPART function provides the specified part of a date, such as the year, month, or day. This function takes two arguments: the part to be returned and the date value. The syntax for this function is:
DATEPART (datepart, date)
Here, the datepart argument specifies the part of the date to be returned, and the date argument represents the date value. The datepart argument can be one of the following:
Argument |
Description |
|---|---|
year |
Returns the year of the date |
quarter |
Returns the quarter of the year |
month |
Returns the month of the year |
dayofyear |
Returns the day of the year |
day |
Returns the day of the month |
week |
Returns the week of the year |
weekday |
Returns the day of the week (1 = Sunday, 2 = Monday, …, 7 = Saturday) |
hour |
Returns the hour of the day |
minute |
Returns the minute of the hour |
second |
Returns the second of the minute |
millisecond |
Returns the millisecond of the second |
The following example shows how to use the DATEPART function:
SELECT DATEPART(year, '2021-01-01')
This will return the year of the date as 2021.
Using the DATEPART function, you can extract any part of a date value that you need for your query or calculation.
DATEADD Function
The DATEADD function adds a specified value to a date and returns a new date. This function takes three arguments: the datepart to be added, the number of datepart intervals, and the date value. The syntax for this function is:
DATEADD (datepart, number, date)
Here, the datepart argument specifies the part of the date to which the number of intervals is added, the number argument specifies the number of intervals to be added, and the date argument represents the date value. The datepart argument can be the same as the datepart values used in the DATEPART function.
The following example shows how to use the DATEADD function:
SELECT DATEADD(day, 30, '2021-01-01')
This will add 30 days to the date ‘2021-01-01’ and return a new date value of ‘2021-01-31’.
Using the DATEADD function, you can perform various calculations on date values, such as adding or subtracting days, months, or years.
DATEDIFF Function
The DATEDIFF function calculates the difference between two dates in terms of a specified datepart. This function takes three arguments: the datepart in which the difference is calculated, the start date value, and the end date value. The syntax for this function is:
DATEDIFF (datepart, startdate, enddate)
Here, the datepart argument specifies the part in which the difference is calculated, the startdate argument represents the start date value, and the enddate argument represents the end date value.
The following example shows how to use the DATEDIFF function:
SELECT DATEDIFF(day, '2021-01-01', '2021-01-31')
This will calculate the difference between the start date ‘2021-01-01’ and the end date ‘2021-01-31’ in terms of days, and return a difference value of 30.
Using the DATEDIFF function, you can compare or calculate the difference between any two date values in any specified datepart.
GETDATE Function
The GETDATE function returns the current system date and time value. This function does not take any arguments. The syntax for this function is:
GETDATE()
The following example shows how to use the GETDATE function:
SELECT GETDATE()
This will return the current date and time value of the system.
The GETDATE function can be used to get the current date and time value, which can be useful for various calculations or queries.
DATEFROMPARTS Function
The DATEFROMPARTS function creates a new date value from the specified year, month, and day values. This function takes three arguments: the year value, the month value, and the day value. The syntax for this function is:
DATEFROMPARTS (year, month, day)
The following example shows how to use the DATEFROMPARTS function:
SELECT DATEFROMPARTS(2021, 1, 1)
This will create a new date value with the year value 2021, the month value 1, and the day value 1.
The DATEFROMPARTS function can be used to create new date values from the specified year, month, and day values.
Frequently Asked Questions About Date Functions in SQL Server
What is the use of date functions in SQL Server?
Date functions in SQL Server are used to manipulate and perform calculations on date and time values. These functions can help you extract specific parts of a date value, add or subtract intervals from a date value, calculate the difference between two dates, and more.
What are some commonly used date functions in SQL Server?
Some commonly used date functions in SQL Server are DATEPART, DATEADD, DATEDIFF, GETDATE, and DATEFROMPARTS.
Can we perform calculations on date values in SQL Server?
Yes, you can perform various calculations on date values in SQL Server using built-in date functions such as DATEADD and DATEDIFF.
What is the syntax of the DATEADD function?
The syntax of the DATEADD function is:
DATEADD (datepart, number, date)
Here, the datepart argument specifies the part of the date to which the number of intervals is added, the number argument specifies the number of intervals to be added, and the date argument represents the date value.
What is the purpose of the GETDATE function?
The GETDATE function is used to get the current system date and time value in SQL Server.
Conclusion
In conclusion, date functions in SQL Server are an important topic for any developer or administrator working with databases. In this article, we discussed some commonly used date functions in SQL Server, including their syntax, usage, and examples. We also provided some frequently asked questions about date functions. By mastering these functions, you can make your SQL queries more efficient and perform various calculations on date values. We hope that you found this article informative and useful. Happy coding, Dev!