SQL Server Convert Datetime

Hello Dev, in this article we are going to dive deep into the world of SQL Server Convert Datetime. We will cover everything from the basics to the most advanced techniques. By the end of this article, you will be a pro in converting datetimes in SQL Server. So, let’s begin!

Introduction

Before we start, let’s define what a datetime is. A datetime is a data type in SQL Server that represents a date and time value. It is used to store values that include both a date and a time component.

Converting datetimes is a common task in SQL Server. You might want to convert a datetime value to a different format, or you might need to convert a string that represents a date and time into a datetime data type. Whatever your requirement might be, SQL Server has many built-in functions that can help you achieve your goal.

In this article, we will be discussing the various datetime conversion functions available in SQL Server, their syntax, examples, and use cases.

Datetime Conversion Functions

SQL Server provides many built-in functions that can be used to convert datetimes into various formats. Let’s discuss some of the most commonly used datetime conversion functions.

CAST Function

The CAST function is used to convert an expression of one data type to another data type. To convert a datetime value to another data type, we can use the CAST function.

The syntax of the CAST function is as follows:

CAST(expression AS data_type)

Let’s see an example:

SELECT CAST('2022-01-01 12:00:00' AS DATE)

In this example, we are converting a string value ‘2022-01-01 12:00:00’ into a date data type using the CAST function.

CONVERT Function

The CONVERT function is similar to the CAST function. It is used to convert an expression of one data type to another data type. However, the CONVERT function provides more flexibility in terms of formatting the output.

The syntax of the CONVERT function is as follows:

CONVERT(data_type, expression, [style])

The style parameter is optional and is used to specify a style for the output format.

Here’s an example:

SELECT CONVERT(VARCHAR(10), GETDATE(), 101)

In this example, we are converting the current datetime value returned by the GETDATE function into a varchar data type with the format ‘mm/dd/yyyy’ using the CONVERT function.

FORMAT Function

The FORMAT function is used to format a value into a string using a specified format. It is available starting from SQL Server 2012.

The syntax of the FORMAT function is as follows:

FORMAT(value, format)

Let’s see an example:

SELECT FORMAT(GETDATE(), 'MM/dd/yyyy')

In this example, we are formatting the current datetime value returned by the GETDATE function into a string with the format ‘MM/dd/yyyy’ using the FORMAT function.

FAQs

Q1. What is the difference between CAST and CONVERT functions?

Both the CAST and CONVERT functions are used to convert an expression of one data type to another data type. The main difference between the two functions is that the CONVERT function provides more flexibility in terms of formatting the output using the style parameter.

Q2. How do I convert a string value to a datetime data type?

To convert a string value to a datetime data type, you can use either the CAST or CONVERT function. Here’s an example:

SELECT CAST('2022-01-01 12:00:00' AS DATETIME)

In this example, we are converting a string value ‘2022-01-01 12:00:00’ into a datetime data type using the CAST function.

Q3. What are some common datetime formats used in SQL Server?

Some of the most commonly used datetime formats in SQL Server are:

1. ‘yyyy-mm-dd hh:mi:ss’
2. ‘mm/dd/yyyy’
3. ‘dd/mm/yyyy’
4. ‘yyyy-mm-dd’

Conclusion

Converting datetimes in SQL Server is a common task that can be achieved using various built-in functions. In this article, we discussed the most commonly used datetime conversion functions, their syntax, examples, and use cases. We also covered some frequently asked questions related to datetime conversion in SQL Server. We hope this article was useful and helped you in your journey to becoming a pro in SQL Server.