> Can you tell me trim() spec, please ? (This problem has been
> discussed in pgsql-jp ML. )
> In trim(trailing 'abc' from '123cbabc') function, 'abc' means
> ~'[abc]'.
> 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().
> How do you think about the trim() spec ?
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.
I'm not sure if SQL3/SQL99 has anything extra to say on this.
position() and substring() seem to be able to do what you want;
select substring('123ab' for position('ab' in '123ab')-1);
gives '123', while
select substring('123ab' for position('d' in '123ab')-1);
gives '123ab', which seems to be the behavior you might be suggesting
for trim().
- Tom