Re: Regular expression to UPPER() a lower case string

On 2022-12-10 13:44:37 +0000, Gianni Ceccarelli wrote:
> On 2022-12-10 "Peter J. Holzer" <hjp-pgsql(at)hjp(dot)at> wrote:
> > > * your logic only works by accident for some languages (try to
> > > upcase a `ß` or a `ı`)
> >
> > This is also true of upper() and lower() and SQL does provide those.
>
> Well…
>
> > select upper('ı');
> ┌───────┐
> │ upper │
> ├───────┤
> │ I │
> └───────┘
> (1 row)

This is I think universally correct. A better example would be
upper('i') which should be 'İ' in Turkish and 'I' in most other
languages.

> > select upper('ß');
> ┌───────┐
> │ upper │
> ├───────┤
> │ ß │
> └───────┘
> (1 row)

This is incorrect according to German spelling rules. It should be
either 'SS' (traditionally) or 'ẞ' (since the introduction of the
upper-case sharp s). However, given the long absence of the ẞ from
official German orthography and the lack of reversability of the ß → SS
mapping it has been (and still is) quite common to leave the ß in lower
case.

> > select upper('ä');
> ┌───────┐
> │ upper │
> ├───────┤
> │ Ä │
> └───────┘
> (1 row)

Correct (in German[1] and probably any other language).

So, what's the point you are trying to make?

> Of course all of this is dependent of locale, too.

Right. But why would that be different for regexp_replace than for
upper/lower)?

hp

[1] Although I have one book which uses ä, ö, ü for lower case but Ae,
Oe, Ue for upper case letters.

--
_ | Peter J. Holzer | Story must make more sense than reality.
|_|_) | |
| | | hjp(at)hjp(dot)at | -- Charles Stross, "Creative writing
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