RE: [HACKERS] SQL92

> Jackson, DeJuan wrote:
> > > > Does the SQL92 standard have to be purchased from the ANSI
> Board?
> > > afaik, yes.
> > >
> > > > Well, my actual question has to do with LIKE.  Could anyone who
> has
> > > a
> > > > copy of a standard send me the PATTERN syntax/meanings for LIKE
> in
> > > > SQL92?
> > >
> > > Well, you may be hoping for more than is in any of your reference
> > > books,
> > > but there isn't any more to tell :)
> > >
> > >   % ==> match any (sub)string
> > >   _ ==> match any single character
> > >   everything else matches itself
> > >
> > > In SQL92 (but not yet in Postgres; can't remember if there is a
> > > workaround):
> > >
> > >   LIKE 'pattern' ESCAPE 'char'
> > >
> > > allows a single character "char" if it precedes the two pattern
> > > matching
> > > characters to demote the "%" or "_" to act like a normal single
> > > character. The Postgres regex stuff is much more powerful.
> > >
> > > Sorry, I think that's it :(
> > >
> > >                     - Tom
> > Well, In all of the major Databases that I have worked with there is
> > also the "[character_set]" matching operator.
> > So a pattern of '[A-D]%' would match all word beginning with "A",
> "B",
> > "C", or "D", and "[^character_set]" matches everything but the set.
> > Looking at the current PgSQL like code this is ignored as well as
> the
> > ESCAPE syntax.  I'm trying to resolve the problem we have of LIKE
> not
> > matching the pattern "%%" to anything even "%".
> > But, looking at the code I see that "%%" or "%%%%%%%%" should be
> equal
> > to "%" so it's not the LIKE matching code that's causing the problem
> > (also, read I'm looking in the wrong spot).
> >
> > Does anybody know if the "[character_set]" stuff is part of the
> > standard?
> The SQL92 LIKE:
>
>     character-string-expression [NOT] LIKE pattern [ESCAPE
> 'escape-char']
>
> allows only the special characters % and _
>
> You need The SQL3 SIMILAR
>
>     character-string-expression [NOT] SIMILAR TO pattern [ESCAPE
> 'escape-char']
>
> in this case pattern can involve additional special characters, not
> just
> % and _ as in LIKE, but every regular expression or "[character_set]"
> like you said. (Refer to "A Guide to SQL Standard 4th edition
> Date-Rarwen, page 505).
>
>      Jose'
Well, I'm not looking for a new operator just trying to clarify what the
scope of the current one should be.  But, thanks for the information,
Jose'.
If you have any clue where in the source-tree LIKE is implemented could
you let me know?
    -DEJ