Re: [SQL] Could someone help me fix my array_list function?

[Joe Conway]

Guy Fraser wrote:

This is what I want to do:

select attribute,array_list(values,1,sizeof(values)) as value from av_list;

Turn :
 attr6 | {val3,val7,val4,val5}

Into :
 attr6 | val3
 attr6 | val7
 attr6 | val4
 attr6 | val5

You didn't mention the version of PostgreSQL. If you're using < 7.3, good luck ;-). If you are using 7.3, the following works:

DROP TABLE mail_aliases;
CREATE TABLE mail_aliases(
a_mailbox text,
a_destination text[]
);

INSERT INTO mail_aliases VALUES ('alias1', '{dest1}');
INSERT INTO mail_aliases VALUES ('alias2', '{dest2,dest1}');
INSERT INTO mail_aliases VALUES ('alias3', '{dest3,dest4}');
INSERT INTO mail_aliases VALUES ('alias4', '{dest3,dest4,dest5}');
INSERT INTO mail_aliases VALUES ('alias5', '{dest6,dest7}');
INSERT INTO mail_aliases VALUES ('alias6', '{dest3,dest7,dest4,dest5}');

CREATE TYPE mail_aliases_list_type AS (a_mailbox text, a_destination_el text);
CREATE OR REPLACE FUNCTION mail_aliases_list() RETURNS SETOF mail_aliases_list_type AS '
DECLARE
rec record;
retrec record;
low int;
high int;
BEGIN
FOR rec IN SELECT a_mailbox, a_destination FROM mail_aliases LOOP
SELECT INTO low
replace(split_part(array_dims(rec.a_destination),'':'',1),''['','''')::int;
SELECT INTO high
replace(split_part(array_dims(rec.a_destination),'':'',2),'']'','''')::int;

FOR i IN low..high LOOP
SELECT INTO retrec rec.a_mailbox, rec.a_destination[i];
RETURN NEXT retrec;
END LOOP;
END LOOP;
RETURN;
END;
' LANGUAGE 'plpgsql';

regression=# SELECT a_mailbox, a_destination_el FROM mail_aliases_list();
a_mailbox | a_destination_el
-----------+------------------
alias1 | dest1
alias2 | dest2
alias2 | dest1
alias3 | dest3
alias3 | dest4
alias4 | dest3
alias4 | dest4
alias4 | dest5
alias5 | dest6
alias5 | dest7
alias6 | dest3
alias6 | dest7
alias6 | dest4
alias6 | dest5
(14 rows)


HTH,

Joe


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