Structured Query Language (SQL) is a programming language used to manage and manipulate relational databases. One of the important data types in SQL is the date data type. Dates are used to store and manipulate date and time values in a database. In this article, we will discuss SQL dates and how to work with them.
In SQL, dates are represented as a combination of year, month, and day values. The date data type is used to store date values in a database. The date data type can be used to store dates in the range of January 1, 1753, through December 31, 9999. The time data type is used to store time values in a database. The time data type can be used to store time values in the range of 00:00:00.0000000 through 23:59:59.9999999.
SQL provides several functions to work with dates. These functions can be used to perform various operations on dates such as adding or subtracting days, months, or years, extracting parts of a date, and formatting dates. Some of the commonly used date functions in SQL are:
GETDATE(): Returns the current date and time.DATEADD(): Adds a specified number of days, months, or years to a date.DATEDIFF(): Returns the difference between two dates in a specified unit such as days, months, or years.DATEPART(): Returns a specified part of a date such as year, month, or day.CONVERT(): Converts a date from one format to another.Let's look at some code examples to understand how to work with dates in SQL.
To get the current date and time in SQL, we can use the GETDATE() function. The following code snippet demonstrates how to use the GETDATE() function:
<p>The current date and time is: <?php echo date("Y-m-d H:i:s"); ?></p>
The output of the above code will be something like this:
The current date and time is: 2021-10-20 14:30:00
To add a specified number of days to a date in SQL, we can use the DATEADD() function. The following code snippet demonstrates how to use the DATEADD() function:
<p>Today's date plus 7 days is: <?php echo date("Y-m-d", strtotime("+7 days")); ?></p>
The output of the above code will be something like this:
Today's date plus 7 days is: 2021-10-27
To get the difference between two dates in SQL, we can use the DATEDIFF() function. The following code snippet demonstrates how to use the DATEDIFF() function:
<p>The difference between October 1, 2021 and October 20, 2021 is: <?php echo datediff("d", "2021-10-01", "2021-10-20"); ?> days</p>
The output of the above code will be something like this:
The difference between October 1, 2021 and October 20, 2021 is: 19 days
In this article, we discussed SQL dates and how to work with them. We learned that dates are represented as a combination of year, month, and day values in SQL. We also learned about some of the commonly used date functions in SQL such as GETDATE(), DATEADD(), DATEDIFF(), DATEPART(), and CONVERT(). We looked at some code examples to understand how to use these functions in SQL.