Oracle/PLSQL: Test a string for an alphanumeric value

Question: In Oracle, I want to know if a string value contains alphanumeric characters only. How can I do this?

Answer: To test a string for alphabetic characters, you could use a combination of the LENGTH, TRIM, AND TRANSLATE functions built into Oracle.

You can use the following command:

LENGTH(TRIM(TRANSLATE(string1, 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ' ')))

string1 is the string value that you are testing

This function will return a null value if string1 is alphanumeric. It will return a value "greater than 0" if string1 contains any non-alphanumeric characters.

For example,

LENGTH(TRIM(TRANSLATE('Tech3', 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ' '))) would return 1

LENGTH(TRIM(TRANSLATE('Tech1Net2', 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ' '))) would return 2

LENGTH(TRIM(TRANSLATE('Tech on the Net', 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ' '))) would return null

Learn more about the translate function.

Learn more about the length function.

Learn more about the trim function.