Oracle regexp_like - only certain characters, numbers and one symbol

Question

SELECT count(*)
FROM dual
WHERE regexp_like ('ABC-123', '^[a-zA-Z0-9]*$');

I would like to use Oracle's regexp_like to only allow the following:

1. A to Z, uppercase and lowercase.
2. All numbers.
3. Symbol -

Answer 1

If you plan to match a hyphen, the ones inbetween a-z, A-Z and 0-9 are not literal hyphens, they are functional characters defining a range.

You need to add a hyphen to the end of the [...]:

^[a-zA-Z0-9-]*$
           ^

To avoid empty matches, use

^[a-zA-Z0-9-]+$
             ^