Thread: RE: [HACKERS] SQL92

RE: [HACKERS] SQL92

From
"Jackson, DeJuan"
Date:
> > 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'
> >
> >
>
> TODO item changed to:
>
>     * add SIMILAR to allow character classes, 'pg_[a-c]%'
So are we going to add the character class support to LIKE or SIMILAR or
both?  Just looking for clarification.  Or are we going to use the regex
code for both?
    -DEJ

Re: [HACKERS] SQL92

From
Bruce Momjian
Date:
> > > 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'
> > >
> > >
> >
> > TODO item changed to:
> >
> >     * add SIMILAR to allow character classes, 'pg_[a-c]%'
> So are we going to add the character class support to LIKE or SIMILAR or
> both?  Just looking for clarification.  Or are we going to use the regex
> code for both?

No idea.  It is just a valid TODO item.

--
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026


Re: [HACKERS] SQL92

From
"Thomas G. Lockhart"
Date:
> >       * add SIMILAR to allow character classes, 'pg_[a-c]%'
> So are we going to add the character class support to LIKE or SIMILAR
> or both?  Just looking for clarification.  Or are we going to use the
> regex code for both?

I would expect us to stay compatible with the standard for LIKE, and
perhaps have a superset of the SQL3 (draft) standard for SIMILAR. I'd
expect it to be a candidate for v6.5, or perhaps for v6.4.x.

But I'm not doing the work, and whoever does has a much stronger vote :)

               - Tom