Re: BUG #4436: (E'\\' LIKE E'\\') => f

Bruce Momjian <bruce@momjian.us> writes:
> Mathieu Fenniak wrote:
>> I noticed that (SELECT E'\\' LIKE E'\\') returns false,

> I believe this is caused because backslash is the default escape
> character for LIKE, so you need:
>     test=> SELECT E'\\' LIKE E'\\\\';

Yeah.  The given case is actually an invalid LIKE pattern.  I wonder
whether we should make LIKE throw error for an invalid pattern.
You get an error for the corresponding case in regex:

regression=# select E'\\' ~ E'\\';
ERROR:  invalid regular expression: invalid escape \ sequence

but IIRC the LIKE code just silently ignores a trailing escape
character.

            regards, tom lane