The TRY_PARSE function in SQL Server is used to convert a string representation of a date and time into a datetime (or other date/time types) format. If the conversion fails, it returns NULL instead of raising an error.
Here’s the basic syntax for using TRY_PARSE:
TRY_PARSE ( string_val AS data_type [ USING culture ] )
Parameters
- string_val: The string expression that you want to convert.
- data_type: The data type that you want to convert to, typically datetime, datetime2, date, or time.
- culture (optional): A culture code that indicates the format of the input string.
Example Usage
Basic Example
Suppose you have a string in the format "MM/DD/YYYY" and you want to convert it to a datetime.
SELECT TRY_PARSE('12/31/2023' AS datetime) AS ParsedDate;
This will convert the string '12/31/2023' to a datetime type representing December 31, 2023.
Using Culture
If the date is in a different format or if your string uses a specific culture-specific format, you can specify the culture. For example, if you're dealing with a date in the format "DD/MM/YYYY" (common in many non-US locales), you can do:
SELECT TRY_PARSE('31/12/2023' AS datetime USING 'en-GB') AS ParsedDate;
Handling Invalid Formats
If the string cannot be converted (e.g., if the format is incorrect or not compatible with the specified culture), TRY_PARSE will return NULL instead of throwing an error:
SELECT TRY_PARSE('invalid date' AS datetime) AS ParsedDate; -- This will return NULL
Important Notes
- Be cautious about the input format and the culture that you specify, as they can significantly affect how the string is interpreted.
- The TRY_PARSE function can be slower than other conversion methods, especially in large datasets, due to its parsing capabilities.
Using TRY_PARSE is a safe way to handle potentially incorrect string data when converting to date and time types in SQL Server.