How to Convert Datetime to Date in SQL Server

Hello, Dev! Are you struggling to convert datetime to date in SQL Server? Look no further than this comprehensive guide. In this article, we will cover everything you need to know about converting datetime to date in SQL Server, including examples, syntax, and frequently asked questions.

Understanding Datetime and Date in SQL Server

Before we dive into datetime to date conversions, let’s first define what datetime and date mean in SQL Server.

Datetime is a data type in SQL Server that represents a date and time value. It can store dates in the range of January 1, 1753, to December 31, 9999, with an accuracy of up to three-hundredths of a second.

Date, on the other hand, is a data type that only stores the date component of a datetime value. It stores dates in the range of January 1, 0001, to December 31, 9999.

Now that we have a basic understanding of datetime and date, let’s move on to converting datetime to date.

Methods for Converting Datetime to Date

There are several methods you can use to convert datetime to date in SQL Server. We will cover the most commonly used ones below.

Using CONVERT Function

The CONVERT function allows you to convert one data type to another in SQL Server. To convert datetime to date using the CONVERT function, you can use the following syntax:

Input	Output
CONVERT(date, ‘2022-01-01 13:30:00.000’)	2022-01-01

In the above example, we are converting a datetime value ‘2022-01-01 13:30:00.000’ to a date value using the CONVERT function. The ‘date’ argument specifies the output data type.

It is important to note that when using the CONVERT function, the input datetime value must be in a valid datetime format.

Using CAST Function

The CAST function also allows you to convert one data type to another in SQL Server. To convert datetime to date using the CAST function, you can use the following syntax:

Input	Output
CAST(‘2022-01-01 13:30:00.000’ AS date)	2022-01-01

In the above example, we are converting a datetime value ‘2022-01-01 13:30:00.000’ to a date value using the CAST function. The ‘AS date’ argument specifies the output data type.

The CAST function is similar to the CONVERT function, but it is more concise and may be easier to read.

Using DATE Function

The DATE function allows you to extract the date component from a datetime value in SQL Server. To extract the date component using the DATE function, you can use the following syntax:

Input	Output
DATEADD(dd, DATEDIFF(dd, 0, ‘2022-01-01 13:30:00.000’), 0)	2022-01-01

In the above example, we are using the DATEADD and DATEDIFF functions to extract the date component from the datetime value ‘2022-01-01 13:30:00.000’. The ‘dd’ argument in DATEADD and DATEDIFF specifies that we are working with days. The ‘0’ argument in DATEDIFF represents the base date, which is January 1, 1900, in SQL Server.

Frequently Asked Questions

What is the difference between datetime and smalldatetime?

Datetime and smalldatetime are both data types in SQL Server that store date and time values. However, smalldatetime stores dates in the range of January 1, 1900, to June 6, 2079, with an accuracy of up to one minute, while datetime stores dates in a wider range with greater accuracy.

What is the default datetime format in SQL Server?

The default datetime format in SQL Server is ‘yyyy-mm-dd hh:mi:ss.mmm’ (e.g. ‘2022-01-01 13:30:00.000’).

How do I format a datetime value in SQL Server?

You can use the CONVERT function to format a datetime value in SQL Server. For example, to format a datetime value as a string in ‘mm/dd/yyyy’ format, you can use the following syntax:

Input	Output
CONVERT(varchar, ‘2022-01-01 13:30:00.000’, 101)	01/01/2022

In the above example, the ‘101’ argument in CONVERT specifies the desired output format.

Can I convert a date value to a datetime value in SQL Server?

Yes, you can convert a date value to a datetime value in SQL Server using the CAST or CONVERT function. For example, to convert a date value ‘2022-01-01’ to a datetime value ‘2022-01-01 00:00:00.000’, you can use the following syntax:

Input	Output
CAST(‘2022-01-01’ AS datetime)	2022-01-01 00:00:00.000

Conclusion

Converting datetime to date in SQL Server may seem daunting at first, but with the methods and examples covered in this article, you should be well-equipped to handle any date-related queries in your SQL Server database. Remember to always double-check your syntax and input values to ensure accurate results. Happy coding!