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 alphanumeric characters, you could use a combination of the LENGTH function, TRIM function, and TRANSLATE function built into Oracle.

You can use the following command:

LENGTH(TRIM(TRANSLATE(string1, 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+-.0123456789', ' ')))

string1

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('Tech on the Net!!!', 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+-.0123456789', ' ')))
Result: 3

LENGTH(TRIM(TRANSLATE('Tech1Net2^', 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+-.0123456789', ' ')))
Result: 1

LENGTH(TRIM(TRANSLATE('Tech on the Net567', 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+-.0123456789', ' ')))
Result: null

Learn more about the TRANSLATE function.

Learn more about the LENGTH function.

Learn more about the TRIM function.