Re: [SQL] substring

Michael J Davis ha scritto:

> I wonder if position is a 6.5 feature?  I am using 6.5.

POSITION function was implemented on v6.2.
José

>
>
>         -----Original Message-----
>         From:   José Soares [SMTP:jose@sferacarta.com]
>         Sent:   Tuesday, April 27, 1999 7:02 AM
>         To:     Nuchanard Chiannilkulchai
>         Cc:     pgsql-sql@hub.org
>         Subject:        Re: [SQL] substring
>
>
>
>         Nuchanard Chiannilkulchai ha scritto:
>
>                 The problem is : select  position ('_' in a ) from table_a
> does not
>                 work.
>                  ERROR:  No such function 'strpos' with the specified
> attributes
>
>                 while  select position('_' in '98-004_c136') ;    give the
> right answer.
>
>                  I wonder how to introduce the attribute , and not the
> constant value.
>
>                 Michael J Davis wrote:
>
>                 > try:
>                 >
>                 > select a, substring(a, 1, position('_' in a) -1) from
> table_a;
>                 >
>                 > I have not tested this.  Not sure if the parameters to
> substring are
>                 > correct.  Also not sure if the -1 is needed.
>                 >
>                 > > -----Original Message-----
>                 > > From: Nuchanard Chiannilkulchai [SMTP:nuch@valigene.com]
>
>                 > > Sent: Monday, April 26, 1999 8:57 AM
>                 > > To:   pgsql-sql@hub.org
>                 > > Subject:      [SQL] substring
>                 > >
>                 > > Hello,
>                 > >
>                 > >     How should I do my query to put a substring value in
> a field, in
>                 > > postgres ( I have 6.4) ?
>                 > >   [snips]
>
>                 > > in sybase, this should be
>                 > >  select a, substring(a,1,charindex('_',a)-1)  from
> table_a
>                 > >  a
>                 > >  ---------------- ----------------
>                 > >  98-004_c136      98-004
>                 > >  98-005_c171      98-005
>                 > >  P124_154         P124
>                 > >
>
>         charindex() is not SQL standard, with PostgreSQL you can
>         use this portable SQL standard query:
>
>         select a, substring(a from 1 for position('_' in a) - 1) as part
> from test;
>         a          |part
>         -----------+------
>         98-004_c136|98-004
>         98-005_c171|98-005
>         P124_154   |P124
>         (3 rows)
>
>         José
>