Regular Expression to return when invalid character found

Question

I have the following regex that checks for a list of valid characters:

^([a-zA-Z0-9+?/:().,' -]){1,35}$

What I now need to do now is search for any existing columns in our DB that invalidates the above regex. I'm using the oracle SQL REGEXP_LIKE command.

The problem I have is I can't seem to negate the above expression and return a value when it finds a character not in the expression eg

"a-valid-filename.xml" => this shouldn't be returned as it's valid.
"an_invalid-filename.xml" => I need to find these ie anything with an invalid character.

The obvious answer to me is to define a list of invalid characters... but that could be a long list.

Answer 1

You can match it against the following regex which uses the [^...] negation character class:

([^a-zA-Z0-9+?/:().,' -])

This will match any single character that is not part of the list of characters that are allowed.

Answer 2

You can negate a character class by inserting a caret as the first character.

Example:

[^y]

The above will match anything that is not y

Answer 3

Try this:

where not regexp_like(col, '^([a-zA-Z0-9+?/:().,'' -]){1,35}$')

or

where regexp_like(col, '[^a-zA-Z0-9+?/:().,'' -]')