[SQL] select result into string's array

[Alberto Asuero Arroyo]

Hi,

I need to store the result of select into an array of string:

/create or replace function search_engine.test/
/(/
/)/
/returns integer as $$/
/declare/
/m_array text[];/
/begin/
/for m_array in select * from my_table loop/
/raise notice 'valor 1: %',m_array;/
/end loop;/
/return 1;/
/end; $$ LANGUAGE plpgsql;/


This launch this errors:

/ERROR: array value must start with "{" or dimension information
SQL state: 22P02
Context: PL/pgSQL function "test" line 4 at FOR over SELECT rows/


Is it possible do this?? May I choose another way?

Thanks in advance

Alberto,



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Re: [SQL] select result into string's array

[A. Kretschmer]

In response to Alberto Asuero Arroyo :
> Hi,
> 
> I need to store the result of select into an array of string:

test=*# select * from foo;
  t
--
 foo
 bar
 batz
(3 rows)

test=*# select array_agg(t) from foo;
   array_agg

 {foo,bar,batz}
(1 row)

Helps that?


Andreas
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Re: [SQL] select result into string's array

[Dmitriy Igrishin]

Hello.

You should use an array constructor:

DECLARE
m_array text[];
[..]
BEGIN
FOR m_array IN SELECT ARRAY[col_1, col_2, col_N] FROM my_table LOOP
[..]
END LOOP;

Regards,
Igrishin Dmitriy.

2009/10/9 Alberto Asuero Arroyo 

> Hi,
>
> I need to store the result of select into an array of string:
>
>/create or replace function search_engine.test/
>/(/
>/)/
>/returns integer as $$/
>/declare/
>/m_array text[];/
>/begin/
>/for m_array in select * from my_table loop/
>/raise notice 'valor 1: %',m_array;/
>/end loop;/
>/return 1;/
>/end; $$ LANGUAGE plpgsql;/
>
>
> This launch this errors:
>
>/ERROR: array value must start with "{" or dimension information
>SQL state: 22P02
>Context: PL/pgSQL function "test" line 4 at FOR over SELECT rows/
>
>
> Is it possible do this?? May I choose another way?
>
> Thanks in advance
>
> Alberto,
>
>
>
> --
> Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-sql
>

Re: [SQL] select result into string's array

[Alberto Asuero Arroyo]

Dmitriy Igrishin wrote:
> Hello.
>
> You should use an array constructor:
>
> DECLARE
> m_array text[];
> [..]
> BEGIN
> FOR m_array IN SELECT ARRAY[col_1, col_2, col_N] FROM my_table LOOP
> [..]
> END LOOP;
>
> Regards,
> Igrishin Dmitriy.
>
> 2009/10/9 Alberto Asuero Arroyo  >
>
> Hi,
>
> I need to store the result of select into an array of string:
>
>/create or replace function search_engine.test/
>/(/
>/)/
>/returns integer as $$/
>/declare/
>/m_array text[];/
>/begin/
>/for m_array in select * from my_table loop/
>/raise notice 'valor 1: %',m_array;/
>/end loop;/
>/return 1;/
>/end; $$ LANGUAGE plpgsql;/
>
>
> This launch this errors:
>
>/ERROR: array value must start with "{" or dimension information
>SQL state: 22P02
>Context: PL/pgSQL function "test" line 4 at FOR over SELECT rows/
>
>
> Is it possible do this?? May I choose another way?
>
> Thanks in advance
>
> Alberto,
>
>
>
> --
> Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org
> )
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-sql
>
>


It's has been really useful for my  to solve the dinamic Record
Introspection problem that I had.

Thanks,

Alberto


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[SQL] Existential quantifier

[Dag-Erling Smørgrav]

Consider the attached schema (filmstars.sql), which is a poorly designed
database of films and actors.  The following query gives me a list of
films in which either Charlie or Martin Sheen starred:

select fs.film.title, fs.film.year
  from fs.film left join fs.star on fs.film.id = fs.star.film
  where fs.star.last = 'Sheen'
  group by fs.film.title, fs.film.year;

Is there a way to do this without the "group by" clause?

DES
-- 
Dag-Erling Smørgrav - d...@des.no

drop schema fs cascade;

create schema fs;

create table fs.film (
  id serial not null primary key,
  title varchar not null unique,
  year integer not null
);

create table fs.star (
  id serial not null primary key,
  film integer not null references fs.film(id),
  last varchar not null,
  first varchar not null,
  unique (film, last, first)
);

insert into fs.film(title, year) values ('Apocalypse Now', 1979);
insert into fs.star(film, last, first)
  select id, 'Sheen', 'Martin' from fs.film where title = 'Apocalypse Now';
insert into fs.star(film, last, first)
  select id, 'Brando', 'Marlon' from fs.film where title = 'Apocalypse Now';
insert into fs.star(film, last, first)
  select id, 'Duvall', 'Robert' from fs.film where title = 'Apocalypse Now';
insert into fs.star(film, last, first)
  select id, 'Ford', 'Harrison' from fs.film where title = 'Apocalypse Now';

insert into fs.film(title, year) values ('Blade Runner', 1982);
insert into fs.star(film, last, first)
  select id, 'Ford', 'Harrison' from fs.film where title = 'Blade Runner';
insert into fs.star(film, last, first)
  select id, 'Young', 'Sean' from fs.film where title = 'Blade Runner';
insert into fs.star(film, last, first)
  select id, 'Hauer', 'Rutger' from fs.film where title = 'Blade Runner';
insert into fs.star(film, last, first)
  select id, 'Hannah', 'Daryl' from fs.film where title = 'Blade Runner';

insert into fs.film(title, year) values ('Platoon', 1986);
insert into fs.star(film, last, first)
  select id, 'Sheen', 'Charlie' from fs.film where title = 'Platoon';
insert into fs.star(film, last, first)
  select id, 'Dafoe', 'Willem' from fs.film where title = 'Platoon';
insert into fs.star(film, last, first)
  select id, 'Berenger', 'Tom' from fs.film where title = 'Platoon';

insert into fs.film(title, year) values ('Wall Street', 1987);
insert into fs.star(film, last, first)
  select id, 'Douglas', 'Michael' from fs.film where title = 'Wall Street';
insert into fs.star(film, last, first)
  select id, 'Sheen', 'Charlie' from fs.film where title = 'Wall Street';
insert into fs.star(film, last, first)
  select id, 'Hannah', 'Daryl' from fs.film where title = 'Wall Street';
insert into fs.star(film, last, first)
  select id, 'Sheen', 'Martin' from fs.film where title = 'Wall Street';

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Re: [SQL] Existential quantifier

[Stephan Szabo]

On Sat, 10 Oct 2009, [utf-8] Dag-Erling Sm??rgrav wrote:

> Consider the attached schema (filmstars.sql), which is a poorly designed
> database of films and actors.  The following query gives me a list of
> films in which either Charlie or Martin Sheen starred:
>
> select fs.film.title, fs.film.year
>   from fs.film left join fs.star on fs.film.id = fs.star.film
>   where fs.star.last = 'Sheen'
>   group by fs.film.title, fs.film.year;
>
> Is there a way to do this without the "group by" clause?

Not at all tested as I don't have access to my db right now, but I think
something like one of these would work:

select fs.film.title, fs.film.year
 from fs.film
 where exists(select 1 from fs.star where fs.film.id = fs.star.film
  and fs.star.last = 'Sheen');

select fs.film.title, fs.film.year
 from fs.film
 where fs.film.id in (select fs.star.film where fs.star.last = 'Sheen');

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Re: [SQL] Existential quantifier

[Richard Albright]

you could use distinct on

select distinct on (fs.film.title, fs.film.year ) title, year
from fs.film left join fs.star on fs.film.id = fs.star.film
  where fs.star.last = 'Sheen';

On Sat, 2009-10-10 at 00:53 +0200, Dag-Erling Smørgrav wrote:
> Consider the attached schema (filmstars.sql), which is a poorly designed
> database of films and actors.  The following query gives me a list of
> films in which either Charlie or Martin Sheen starred:
> 
> select fs.film.title, fs.film.year
>   from fs.film left join fs.star on fs.film.id = fs.star.film
>   where fs.star.last = 'Sheen'
>   group by fs.film.title, fs.film.year;
> 
> Is there a way to do this without the "group by" clause?
> 
> DES
> plain text document attachment (filmstars.sql)
> drop schema fs cascade;
> 
> create schema fs;
> 
> create table fs.film (
>   id serial not null primary key,
>   title varchar not null unique,
>   year integer not null
> );
> 
> create table fs.star (
>   id serial not null primary key,
>   film integer not null references fs.film(id),
>   last varchar not null,
>   first varchar not null,
>   unique (film, last, first)
> );
> 
> insert into fs.film(title, year) values ('Apocalypse Now', 1979);
> insert into fs.star(film, last, first)
>   select id, 'Sheen', 'Martin' from fs.film where title = 'Apocalypse Now';
> insert into fs.star(film, last, first)
>   select id, 'Brando', 'Marlon' from fs.film where title = 'Apocalypse Now';
> insert into fs.star(film, last, first)
>   select id, 'Duvall', 'Robert' from fs.film where title = 'Apocalypse Now';
> insert into fs.star(film, last, first)
>   select id, 'Ford', 'Harrison' from fs.film where title = 'Apocalypse Now';
> 
> insert into fs.film(title, year) values ('Blade Runner', 1982);
> insert into fs.star(film, last, first)
>   select id, 'Ford', 'Harrison' from fs.film where title = 'Blade Runner';
> insert into fs.star(film, last, first)
>   select id, 'Young', 'Sean' from fs.film where title = 'Blade Runner';
> insert into fs.star(film, last, first)
>   select id, 'Hauer', 'Rutger' from fs.film where title = 'Blade Runner';
> insert into fs.star(film, last, first)
>   select id, 'Hannah', 'Daryl' from fs.film where title = 'Blade Runner';
> 
> insert into fs.film(title, year) values ('Platoon', 1986);
> insert into fs.star(film, last, first)
>   select id, 'Sheen', 'Charlie' from fs.film where title = 'Platoon';
> insert into fs.star(film, last, first)
>   select id, 'Dafoe', 'Willem' from fs.film where title = 'Platoon';
> insert into fs.star(film, last, first)
>   select id, 'Berenger', 'Tom' from fs.film where title = 'Platoon';
> 
> insert into fs.film(title, year) values ('Wall Street', 1987);
> insert into fs.star(film, last, first)
>   select id, 'Douglas', 'Michael' from fs.film where title = 'Wall Street';
> insert into fs.star(film, last, first)
>   select id, 'Sheen', 'Charlie' from fs.film where title = 'Wall Street';
> insert into fs.star(film, last, first)
>   select id, 'Hannah', 'Daryl' from fs.film where title = 'Wall Street';
> insert into fs.star(film, last, first)
>   select id, 'Sheen', 'Martin' from fs.film where title = 'Wall Street';
-- 
Rick Albright
Senior Quantitative Analyst
Insiderscore LLC
ralbri...@insiderscore.com


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Re: [SQL] Existential quantifier

[Dag-Erling Smørgrav]

Richard Albright  writes:
> you could use distinct on
>
> select distinct on (fs.film.title, fs.film.year ) title, year
> from fs.film left join fs.star on fs.film.id = fs.star.film
>   where fs.star.last = 'Sheen';

Thanks, I didn't know about "distinct on".  This version uses the
primary (surrogage) key:

select distinct on (fs.film.id) fs.film.title, fs.film.year
  from fs.film left join fs.star on fs.film.id = fs.star.film
  where fs.star.last = 'Sheen';

DES
-- 
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Re: [SQL] Existential quantifier

[Dag-Erling Smørgrav]

Stephan Szabo  writes:
> Not at all tested as I don't have access to my db right now, but I think
> something like one of these would work:
>
> select fs.film.title, fs.film.year
>  from fs.film
>  where exists(select 1 from fs.star where fs.film.id = fs.star.film
>   and fs.star.last = 'Sheen');

Ah, that was exactly what I was looking for.

> select fs.film.title, fs.film.year
>  from fs.film
>  where fs.film.id in (select fs.star.film where fs.star.last = 'Sheen');

ITYM

select fs.film.title, fs.film.year
 from fs.film
 where fs.film.id in (
   select fs.star.film from fs.star where fs.star.last = 'Sheen'
 );

(missing FROM)

DES
-- 
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Re: [SQL] Existential quantifier

[Stephan Szabo]

On Sat, 10 Oct 2009, [utf-8] Dag-Erling Sm??rgrav wrote:

> Stephan Szabo  writes:
> > Not at all tested as I don't have access to my db right now, but I think
> > something like one of these would work:
> >
> > select fs.film.title, fs.film.year
> >  from fs.film
> >  where exists(select 1 from fs.star where fs.film.id = fs.star.film
> >   and fs.star.last = 'Sheen');
>
> Ah, that was exactly what I was looking for.
>
> > select fs.film.title, fs.film.year
> >  from fs.film
> >  where fs.film.id in (select fs.star.film where fs.star.last = 'Sheen');
>
> ITYM
>
> select fs.film.title, fs.film.year
>  from fs.film
>  where fs.film.id in (
>select fs.star.film from fs.star where fs.star.last = 'Sheen'
>  );
>
> (missing FROM)

Yeah, that'd be necessary. You might want to try them on a realistic data
set to see how the various options are planned.

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