Обсуждение: String Comparison / Embedded Spaces

Does the PostgreSQL string comparison operator remove embedded spaces in
a string before comparing?  Here is a query I'm issuing (notice the
space between A and C in the first string):

select version();
select ('A C' < 'AB') as result;

the result that comes back is:

version

-------------------------------------------------------------------------------------------------------
PostgreSQL 7.3.3 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.2.2
20030222 (Red Hat Linux 3.2.2-5)

result
------
f

I searched the list archives and could not find a mention of this.
Shouldn't the result of the comparison be true, not false?

--
Ken Schenke

On Tue, 22 Jul 2003, Ken Schenke wrote:

> Does the PostgreSQL string comparison operator remove embedded spaces in
> a string before comparing?  Here is a query I'm issuing (notice the
> space between A and C in the first string):
>
> select version();
> select ('A C' < 'AB') as result;
>
> the result that comes back is:
>
> version
>
> -------------------------------------------------------------------------------------------------------
> PostgreSQL 7.3.3 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.2.2
> 20030222 (Red Hat Linux 3.2.2-5)
>
> result
> ------
> f
>
> I searched the list archives and could not find a mention of this.
> Shouldn't the result of the comparison be true, not false?

That depends on the locale you have set for collation.  If it's en_US
(for example) spaces and some symbols don't act like you'd expect.
'AB' < 'A B' < 'AC' < 'A C' I believe.

On Wed, 2003-07-23 at 00:46, Stephan Szabo wrote:
> On Tue, 22 Jul 2003, Ken Schenke wrote:
>
> > Does the PostgreSQL string comparison operator remove embedded spaces in
> > a string before comparing?  Here is a query I'm issuing (notice the
> > space between A and C in the first string):
> >
> > select version();
> > select ('A C' < 'AB') as result;
> >
> > the result that comes back is:
> >
> > version
> >
> > -----------------------------------------------------------------------
> > PostgreSQL 7.3.3 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.2.2
> > 20030222 (Red Hat Linux 3.2.2-5)
> >
> > result
> > ------
> > f
> >
> > I searched the list archives and could not find a mention of this.
> > Shouldn't the result of the comparison be true, not false?
>
> That depends on the locale you have set for collation.  If it's en_US
> (for example) spaces and some symbols don't act like you'd expect.
> 'AB' < 'A B' < 'AC' < 'A C' I believe.

My system is definitely C locale.


template1=# select version();
                                    version
-------------------------------------------------------------------------
 PostgreSQL 7.3.3 on i386-pc-linux-gnu, compiled by GCC gcc (GCC) 3.3
(Debian)
(1 row)

template1=# select ('A C' < 'AB') as result;
 result
--------
 t
(1 row)



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| Ron Johnson, Jr.        Home: ron.l.johnson@cox.net             |
| Jefferson, LA  USA                                              |
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