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

Hello Dev, are you having trouble converting strings to dates in SQL Server? If yes, then you have come to the right place. In this article, we will cover everything you need to know about converting SQL Server string to date. We will go through the different methods available and their pros and cons. So, let’s get started!

Understanding Date and Time Data Types in SQL Server

In SQL Server, there are a few different data types that represent date and time. These include:

Data Type	Description
DATE	Represents a date without a time component
TIME	Represents a time without a date component
DATETIME	Represents a date and time
SMALLDATETIME	Represents a date and time with a smaller range than DATETIME
DATETIMEOFFSET	Represents a date and time with an offset from Coordinated Universal Time (UTC)

Now, let’s dive into the different methods you can use to convert a SQL Server string to date.

Method 1: Using CAST or CONVERT Functions

The most common method to convert a string to date in SQL Server is by using the CAST or CONVERT functions. These functions can convert strings to date, time, or datetime data types. Here’s an example:

SELECT CAST('2022-01-01' AS DATE);SELECT CONVERT(DATE, '2022-01-01');

Both of these queries will return the same result: January 1st, 2022. The first query uses the CAST function, while the second one uses the CONVERT function.

Using CAST or CONVERT with Different Date Formats

In some cases, the date string may not be in the standard YYYY-MM-DD format. In such situations, you can use the optional style parameter to specify the date format. Here’s an example:

SELECT CAST('01/01/2022' AS DATE);SELECT CONVERT(DATE, '01/01/2022', 101);

Both of these queries will return the same result: January 1st, 2022. The 101 parameter in the second query specifies that the date string is in the MM/DD/YYYY format.

Using CAST or CONVERT with Different Date and Time Formats

You can also use the CAST or CONVERT functions to convert strings with both date and time components. Here’s an example:

SELECT CAST('2022-01-01 01:30:00' AS DATETIME);SELECT CONVERT(DATETIME, '2022-01-01 01:30:00');

Both of these queries will return the same result: January 1st, 2022 at 1:30 AM.

Method 2: Using PARSE Function

The PARSE function is another method to convert strings to date in SQL Server. This function is available from SQL Server 2012 onwards. Here’s an example:

SELECT PARSE('January 1, 2022' AS DATE USING 'en-US');

This query will return the date January 1st, 2022. The USING ‘en-US’ parameter specifies the language and region to use for parsing the string.

Using PARSE with Different Date Formats

The PARSE function can handle a wide range of date formats. Here’s an example:

SELECT PARSE('01/01/22' AS DATE USING 'en-US');

This query will return the date January 1st, 2022. The USING ‘en-US’ parameter specifies the language and region to use for parsing the string.

Method 3: Using TRY_CONVERT or TRY_PARSE Functions

If the string you’re trying to convert is not in a valid date format, the CAST, CONVERT, and PARSE functions will return an error. To avoid this, you can use the TRY_CONVERT or TRY_PARSE functions. Here’s an example:

SELECT TRY_CONVERT(DATE, 'January 1st, 2022');SELECT TRY_PARSE('2022-01-01' AS DATE);

Both of these queries will return NULL instead of an error if the conversion fails.

FAQ

Can I Convert a String to Time or Datetime Data Types?

Yes, you can use the same methods to convert a string to a TIME or DATETIME data type. Here’s an example:

SELECT CAST('01:30:00' AS TIME);SELECT CONVERT(TIME, '01:30:00');

Both of these queries will return the time 1:30 AM.

What Date Formats Are Supported by CAST and CONVERT Functions?

The CAST and CONVERT functions support a wide range of date and time formats. You can find the list of supported formats in the official Microsoft documentation.

Can I Convert a String to DATEIMEOFFSET Data Type?

Yes, you can use the same methods to convert a string to a DATETIMEOFFSET data type. Here’s an example:

SELECT CAST('2022-01-01 01:30:00 -08:00' AS DATETIMEOFFSET);SELECT CONVERT(DATETIMEOFFSET, '2022-01-01 01:30:00 -08:00');

Both of these queries will return the datetimeoffset January 1st, 2022 at 1:30 AM with an offset of -08:00.

Can I Convert a String to a Different Date Format?

Yes, you can use the CONVERT function to convert a string to a different date format. Here’s an example:

SELECT CONVERT(VARCHAR(20), CAST('2022-01-01' AS DATE), 106);

This query will return the date string in the format dd mon yyyy (e.g. 01 Jan 2022).

What is the Difference Between CAST and CONVERT Functions?

The CAST and CONVERT functions are similar, but there are some differences. The CAST function is ANSI-standard, while the CONVERT function is specific to SQL Server. The CONVERT function allows more flexibility in converting between different data types and formats.

Conclusion

Converting SQL Server string to date is a common task in database programming. In this article, we have covered the different methods available and their pros and cons. Whether you prefer to use the CAST, CONVERT, PARSE, or TRY_CONVERT/TRY_PARSE functions, you should be able to convert any string to date in SQL Server. We hope that this guide has been helpful to you, Dev!