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

Hi Dev, are you struggling with converting a string to a date format in SQL Server? You’ve come to the right place! In this article, we’ll guide you through the different methods and functions you can use to convert a string to a date in SQL Server. Let’s get started!

Understanding Date Formats in SQL Server

Before we dive into the different ways to convert a string to a date, let’s first understand the different date formats in SQL Server.

SQL Server supports different date formats, such as:

Date Format	Description
yyyy-mm-dd	ISO date format
mm/dd/yyyy	US date format
dd/mm/yyyy	UK date format

It’s important to note that date formats can vary depending on the language and system settings of your SQL Server.

Method 1: Using the CONVERT Function

The CONVERT function is one of the most commonly used functions for converting a string to a date in SQL Server. Here’s the basic syntax:

CONVERT(DATETIME, string_expression, style)

The first parameter, DATETIME, specifies the data type to which you want to convert the string. The second parameter, string_expression, is the string value that you want to convert. The third parameter, style, specifies the format of the string.

Here’s an example:

SELECT CONVERT(DATETIME, '02/14/2022', 101)

In this example, we’re converting the string ’02/14/2022′ to a datetime value, using the 101 style which corresponds to the mm/dd/yyyy format.

Method 2: Using the TRY_CONVERT Function

The TRY_CONVERT function is similar to the CONVERT function, but it’s a bit more flexible. Here’s the basic syntax:

TRY_CONVERT(DATETIME, string_expression, style)

The TRY_CONVERT function attempts to convert the string to the specified data type. If the conversion fails, it returns NULL instead of generating an error. Here’s an example:

SELECT TRY_CONVERT(DATETIME, '2022-02-14')

In this example, we’re attempting to convert the string ‘2022-02-14’ to a datetime value using the TRY_CONVERT function. Since the string is in ISO format, we don’t need to specify a style parameter.

Method 3: Using the CAST Function

The CAST function is another commonly used function for converting a string to a date in SQL Server. Here’s the basic syntax:

CAST(string_expression AS DATETIME)

The CAST function converts the string_expression to the specified data type, which in this case is DATETIME. Here’s an example:

SELECT CAST('02/14/2022' AS DATETIME)

In this example, we’re converting the string ’02/14/2022′ to a datetime value using the CAST function.

FAQs

Q: What happens if the string format is not recognized by the conversion function?

A: If the string format is not recognized by the conversion function, an error will be generated. To avoid this, you can use the TRY_CONVERT function which returns NULL instead of generating an error.

Q: Can I use the same conversion function for all date formats?

A: No, you need to specify the correct style parameter for each date format. Make sure to check the documentation for the correct style codes.

Q: Can I use variables instead of hardcoded strings in the conversion functions?

A: Yes, you can use variables instead of hardcoded strings. Just make sure that the variable contains a valid date string in the correct format.

Q: Is there a function to convert a datetime value to a string?

A: Yes, the CONVERT function can also be used to convert a datetime value to a string. Here’s an example:

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

In this example, we’re using the CONVERT function to convert the current date and time to a string in the mm/dd/yyyy format.

Conclusion

Converting a string to a date in SQL Server can be a bit challenging, but with the right functions and syntax, it can be done easily. We hope this article has helped you understand the different methods and functions you can use to convert a string to a date in SQL Server. Happy coding, Dev!