Обсуждение: SIMILAR TO bug?

Folks,

Perhaps I've misunderstood this, but in PostgreSQL 8.3.5, I get
disparate results from ~ and SIMILAR TO.  For example:

This gives an unexpected result:

davidfetter@davidfetter=# SELECT 'abc' SIMILAR TO '^[a]';?column? 
----------f
(1 row)

This one is what I expected.

davidfetter@davidfetter=# SELECT 'abc' ~ '^[a]';?column? 
----------t
(1 row)

Did I misunderstand what SIMILAR TO does, or...?

Cheers,
David.
-- 
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
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David Fetter wrote:
> Folks,
> 
> Perhaps I've misunderstood this, but in PostgreSQL 8.3.5, I get
> disparate results from ~ and SIMILAR TO.  For example:

Did you read the docs?  ^ is not an anchor.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

David Fetter wrote:
> Folks,
> 
> Perhaps I've misunderstood this, but in PostgreSQL 8.3.5, I get
> disparate results from ~ and SIMILAR TO.  For example:
> 
> This gives an unexpected result:
> 
> davidfetter@davidfetter=# SELECT 'abc' SIMILAR TO '^[a]';
>  ?column? 
> ----------
>  f
> (1 row)
> 
> This one is what I expected.
> 
> davidfetter@davidfetter=# SELECT 'abc' ~ '^[a]';
>  ?column? 
> ----------
>  t
> (1 row)
> 
> Did I misunderstand what SIMILAR TO does, or...?

Well, SIMILAR TO is not the same thing as ~.  For example, ^ is not a 
special character in its pattern language.