Re: trim() spec

On Tue, Jun 13, 2000 at 10:45:07AM -0400, Tom Lane wrote:
> Thomas Lockhart <lockhart(at)alumni(dot)caltech(dot)edu> writes:
> >> If trim(trailing 'abc' from '123cbabc') returns "123cb", current
> >> trim() spec is broken. However, the spec that 'abc' means ~'[abc]'
> >> is ugly. It seems that this ugly spec isn't used for any kind of
> >> functions argument and SQL expression except for trim().
>
> > afaict, the SQL92 spec for trim() requires a single character as the
> > first argument; allowing a character string is a Postgres extension. On
> > the surface, istm that this extension is in the spirit of the SQL92
> > spec, in that it allows trimming several possible characters.
>
> MySQL's crashme list has some useful information about this: they
> indicate whether an implementation considers a multi-char TRIM argument
> to be a set (our way) or a substring (MySQL does it that way, for one).
> So there's precedent for both sides.
>
> Given that our trim() code claims to exist for Oracle compatibility,
> I'd have assumed that its handling of multi-char arguments followed
> Oracle. But the crashme list doesn't show Oracle as supporting either
> semantics. Can someone with access to Oracle check this?

Oracle 8i gives you an error if you give a multi-character argument
to TRIM. So anything that worked with Oracle would work the same with
us.

Richard