How to determine if a string is alphanumeric in PostgreSQL?

In PostgreSQL, you can use the isalnum function to determine if a string is alphanumeric or not. The isalnum function returns TRUE if all characters in the string are either alphabetic or numeric, and FALSE otherwise.

Here is an example of how to use the isalnum function in PostgreSQL:

SELECT isalnum(‘hello123’); — Returns TRUE
SELECT isalnum(‘Hello, world!’); — Returns FALSE
SELECT isalnum(‘12345’); — Returns TRUE

In the first example, the isalnum function returns TRUE because all characters in the string ‘hello123’ are either alphabetic or numeric. In the second example, the isalnum function returns FALSE because the string ‘Hello, world!’ contains non-alphanumeric characters. In the third example, the isalnum function returns TRUE because the string ‘12345’ contains only numeric characters.

Real-life data examples of using the isalnum function in PostgreSQL can be found in various applications that handle user input or data validation. For example, a web application that allows users to register for an account might use the isalnum function to validate the username field, ensuring that it contains only alphanumeric characters. Similarly, a data analytics application might use the isalnum function to validate input data before processing it, to ensure that only valid data is used in the analysis.

About Shiv Iyer 456 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.