Convert Date Time to Date SQL Server: A Comprehensive Guide for Dev

Hello Dev, if you’re working with SQL Server, you know how important it is to be able to manipulate dates and times. In this article, we’ll explore how to convert date time to date in SQL Server. We’ll cover everything from the basic syntax to more advanced techniques. Let’s dive in!

Understanding Date and Time in SQL Server

Before we get started, it’s important to understand how SQL Server stores dates and times. Dates are stored as a numeric value representing the number of days since January 1, 1900. Times are stored as a numeric value representing the fraction of a day. The combination of these values creates a datetime data type in SQL Server.

To convert a datetime value to a date value, we need to remove the time portion of the datetime value. There are several ways to do this in SQL Server, depending on your needs. Let’s explore some of the most common methods.

Method 1: Using the CAST Function

The CAST function is the most basic way to convert datetime to date in SQL Server. It allows us to convert a datetime value to a date value by simply specifying the date data type in the CAST function. Here’s the syntax:

Syntax	Description
CAST(datetime AS date)	Converts a datetime value to a date value

Here’s an example:

SELECT CAST(GETDATE() AS date);

The above query will return the current date without the time portion.

When using the CAST function, keep in mind that it will round up or down the time portion of the datetime value. If you need more control over the rounding, you can use the CONVERT function.

Method 2: Using the CONVERT Function

The CONVERT function allows for more advanced datetime to date conversions in SQL Server. It allows us to specify a style parameter to control the formatting of the date value. Here’s the syntax:

Syntax	Description
CONVERT(date, datetime, style)	Converts a datetime value to a date value with the specified style

Here’s an example:

SELECT CONVERT(date, GETDATE(), 101);

The above query will return the current date in the format MM/DD/YYYY.

There are many different style values you can use with the CONVERT function, depending on your needs. Here are some of the most common:

Style	Description
101	MM/DD/YYYY
102	YYYY.MM.DD
103	DD/MM/YYYY
110	YYYY-MM-DD

Method 3: Using the DATEADD and DATEDIFF Functions

The DATEADD and DATEDIFF functions allow us to manipulate date values in SQL Server. By using these functions, we can add or subtract a certain number of days, months, or years from a datetime value. Here’s the syntax:

Syntax	Description
DATEADD(interval, number, datetime)	Adds a certain number of intervals to a datetime value
DATEDIFF(interval, datetime1, datetime2)	Returns the number of intervals between two datetime values

Here’s an example:

SELECT DATEADD(day, DATEDIFF(day, 0, GETDATE()), 0);

The above query will return the current date without the time portion.

When using the DATEADD and DATEDIFF functions, keep in mind that the interval parameter must match the data type of the datetime values you are working with.

Frequently Asked Questions

What is the difference between datetime and date in SQL Server?

Datetime is a data type that stores both date and time values. Date is a data type that stores only date values without the time portion.

How do I get the current date and time in SQL Server?

You can use the GETDATE() function to get the current date and time in SQL Server. The function returns a datetime value, which can be manipulated using the techniques we’ve covered in this article.

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

You can use the CONVERT or CAST functions to convert a string to a date value in SQL Server. The syntax and style parameter will depend on the format of the string you are working with.

How do I add or subtract a certain number of days from a date value in SQL Server?

You can use the DATEADD function to add or subtract a certain number of days from a date value in SQL Server. Here’s an example:

SELECT DATEADD(day, 7, '2022-01-01');

The above query will add 7 days to the date ‘2022-01-01’ and return the result as a date value.

How do I compare date values in SQL Server?

You can use comparison operators like =, <, and > to compare date values in SQL Server. When comparing datetime values, keep in mind that the time portion will also be compared. If you want to compare only the date portion, you’ll need to use one of the techniques we’ve covered in this article to remove the time portion.

Conclusion

Converting datetime to date in SQL Server is a common task for developers. By using the methods we’ve covered in this article, you can easily manipulate date values to suit your needs. Whether you’re using the CAST function, the CONVERT function, or the DATEADD and DATEDIFF functions, you’ll be able to get the results you need. Keep these techniques in mind the next time you need to work with date values in SQL Server.