Re: [mmoncure@gmail.com: Re: [GENERAL] array_to_set functions]

On Aug 8, 2007, at 11:41 , Decibel! wrote:

> On Tue, Aug 07, 2007 at 10:18:32PM -0700, Jeremy Drake wrote:

>> select * from information_schema._pg_expandarray(ARRAY['foo',
>> 'bar', 'baz']);
>> x | n
>> -----+---
>> foo | 1
>> bar | 2
>> baz | 3
>> (3 rows)
>>
>> Not exactly well documented or well known, but it works.
>
> Worse than that, that's something that's entirely internal and could
> change at any release. The fact that it exists for info_schema
> indicates
> further need for these functions to exist in the backend.

Personally, I think expandarray is more appropriate and its
functionality probably more generally useful, as it identifies the
array indices as well. Note you can also rename the columns.

select * from information_schema._pg_expandarray(ARRAY['foo', 'bar',
'baz']) as b(a,i);
a | i
-----+---
foo | 1
bar | 2
baz | 3
(3 rows)

array_to_set really isn't, as AFAICS it didn't guarantee element
uniqueness (but that's just a naming issue).

Michael Glaesemann
grzm seespotcode net