Re: Regular expression not working [^xyz]

On Mon, 2 Oct 2000, Stuart Peters wrote:

> \connect - postgres
> CREATE TABLE "bug" (
>          "title" text
> );
> COPY "bug" FROM stdin;
> abcdefghijklm
> nopqrstuvwxyz
> aeiou
> \.
> 
> 
> 
> The following queries work as expected, EXCEPT for [2].  I believe 
> that [2] and [3] should return identical results, but [2] simply 
> lists ALL titles:
> 
> [1]  select title from bug where title ~* '[ae]';
> 
>        Lists titles that contain one of the letters a or e: WORKS
> 
> [2]  select title from bug where title ~* '[^ae]';
> 
>        Lists ALL titles rather than those that don't contain a or e: 
> DOESN'T WORK
>        (Note: 'select title from bug where title ~* '[^a];' does not work either

No, that will match any title with at least one character that is not an
a or e.  It you want a match for all characters not a or e it's 
~* '^[^ae]*$'

If you were to put into bug a row like a or ae or e, that wouldn't match
on 2, but abcde... would match because there exists a character other than
a or e.