AW: Yet another LIKE-indexing scheme - Mailing list pgsql-hackers

From Zeugswetter Andreas SB
Subject AW: Yet another LIKE-indexing scheme
Date
Msg-id 11C1E6749A55D411A9670001FA687963368069@sdexcsrv1.f000.d0188.sd.spardat.at
Whole thread Raw
Responses Re: Yet another LIKE-indexing scheme
List pgsql-hackers
> On Sat, Sep 02, 2000 at 01:39:47PM -0400, Tom Lane wrote:
> > > So what happens with "WHERE name like 'Czec%`" ?
> > 
> > Our existing code fails because it generates WHERE name >= 
> 'Czec' AND
> > name < 'Czed'; it will therefore not find names beginning 'Czech'
> > because those are in another part of the index, between 'Czeh' and
> > 'Czei'.  But WHERE name >= 'Cze' AND name < 'Czf' would work.
> 
> (OK, I haven't read the previous discussion.  Guilty, m'lud)
> 
> Why should it?  If 'ch' is one letter, then surely 'czech' isn't LIKE
> 'czec%'.  Because 'czec%' has a second c, wheres, 'czech' only has one
> 'c' and one 'ch'?

Indeed an interesting interpretation, but what I guess makes it bogus is
that
words can exist that have a h after the c that do not represent the ch
character.

Andreas


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