How to Convert a String to a Number in Oracle

Learn the different methods for converting strings to numbers in Oracle SQL, including explicit conversion functions and implicit type conversion techniques. Discover the best practices and considerations to ensure accurate data handling in your database queries.
---
Disclaimer/Disclosure: Some of the content was synthetically produced using various Generative AI (artificial intelligence) tools; so, there may be inaccuracies or misleading information present in the video. Please consider this before relying on the content to make any decisions or take any actions etc. If you still have any concerns, please feel free to write them in a comment. Thank you.
---
When working with Oracle SQL, it's common to encounter scenarios where you need to convert a string into a number. This conversion can be necessary for various reasons, such as performing mathematical operations or comparing numeric values. Oracle provides several methods to achieve this conversion, ranging from explicit conversion functions to implicit type conversion techniques.

Using Explicit Conversion Functions

TO_NUMBER Function: The TO_NUMBER function in Oracle converts a character string to a number. Its syntax is straightforward:

[[See Video to Reveal this Text or Code Snippet]]

string: The input string that you want to convert to a number.

format (optional): Specifies the format of the input string. This parameter is useful when the string contains non-numeric characters or follows a specific format.

nls_params (optional): Allows you to specify the language-dependent behavior of the conversion process.

Example:

[[See Video to Reveal this Text or Code Snippet]]

CAST Function: The CAST function converts one built-in datatype or collection-typed value into another datatype or collection type. You can use it to explicitly convert a string to a numeric datatype.

[[See Video to Reveal this Text or Code Snippet]]

Example:

[[See Video to Reveal this Text or Code Snippet]]

Implicit Type Conversion

Oracle also performs implicit type conversion when appropriate. For instance, if you use a string in a numeric context, Oracle will attempt to convert it to a number automatically. However, relying on implicit conversion can sometimes lead to unexpected results or errors, so it's generally recommended to use explicit conversion functions for clarity and precision.

Considerations

Data Validation: Before converting a string to a number, ensure that the string contains valid numeric data. Otherwise, the conversion may fail or produce incorrect results.

Error Handling: Implement error handling mechanisms, such as TRY...CATCH blocks in PL/SQL, to gracefully handle conversion errors and prevent query failures.

Performance: Evaluate the performance implications of string-to-number conversion in your queries, especially when dealing with large datasets or frequent conversions.

By understanding these conversion techniques and considerations, you can effectively handle string-to-number conversions in Oracle SQL, ensuring accurate data manipulation and query results.