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For those seeking to deepen their understanding of SQL, an encounter with the TRY_CAST and TRY_CONVERT functions is inevitable. These two functions are vital tools within the SQL landscape and unlock a high degree of flexibility when dealing with a variety of data. But, you might ponder upon the question “what exactly are these functions and how do they work?”
TRY_CAST Function
TRY_CAST function in SQL Server is used to transform the data type of a value into another data type. It is crucial when we deal with data type conversion of values. If the conversion is successful, it returns the value as the specified data_type. If the conversion is not successful, it returns NULL. Here’s an example:
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SELECT TRY_CAST('20221101' AS DATETIME) AS Result; |
This statement returns the date ‘2022-11-01 00:00:00.000’. It successfully converts the string to a date. If it can’t make the conversion, it just returns NULL:
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SELECT TRY_CAST('InvalidDate' AS DATETIME) AS Result; |
TRY_CONVERT Function
The TRY_CONVERT function is similar to TRY_CAST function. It converts a value to a specified data type and if the conversion is not possible it returns NULL. However, TRY_CONVERT provides more flexibility because it supports using the style parameter. Here’s an example:
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SELECT TRY_CONVERT(DATETIME, 'July 31, 2022', 107) AS Result; |
This statement returns ‘2022-07-31 00:00:00.000’ because the string date ‘July 31, 2022’ is correctly converted to a date. If you give it a string that it can’t convert, it returns NULL:
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SELECT TRY_CONVERT(DATETIME, 'InvalidDate', 107) AS Result; |
Conclusion
By using TRY_CAST and TRY_CONVERT functions, developers can avoid common errors associated with data type conversion during database operations. It’s a much safer way to handle such conversions as we catch potential conversion errors in the most graceful manner possible by returning NULLs instead of throwing exceptions.