"Eric Noriega" <noriega(at)gwu(dot)edu> writes:
> db=# select 'tab' similar to 'a|b';
> ?column?
> ----------
> t
Yeah, this is a bug ... the cause can be seen by looking at the
underlying similar_escape() function, which converts a SIMILAR TO
pattern into a POSIX regex pattern:
regression=# select similar_escape('(a|b)', null);
similar_escape
----------------
^(a|b)$
(1 row)
regression=# select similar_escape('a|b', null);
similar_escape
----------------
^a|b$
(1 row)
regression=#
I believe that in the second case, ^ and $ bind more tightly than |
per POSIX rules. So we need to put parens around the pattern to
prevent that.
Thanks for the report!
regards, tom lane