Re: [GENERAL] Turning a subselect into an array

#1

Thanks again for the help. I did manage to find that after a bunch of
searching in the mailing list. There should really be a portion of the
docs dedicated to array handling.

On Fri, Oct 29, 2004 at 10:40:57PM -0600, Michael Fuhr wrote:

Quote:

On Fri, Oct 29, 2004 at 05:13:02PM -0500, Jim C. Nasby wrote:
Ok, next stupid question that I can't find in the docs... How would I
join a table to an array? IE: if I have an array of primary keys for
some table and I want to get the name field from that table and turn it
back into an array, how would I do that?

See the "Subquery Expressions" and "Row and Array Comparisons"
sections in the PostgreSQL documentation:

http://www.postgresql.org/docs/7.4/s...-subquery.html
http://www.postgresql.org/docs/7.4/s...mparisons.html

If I understand you correctly, this should work:

SELECT ARRAY(SELECT name FROM foo WHERE id = ANY(ARRAY[1,2,3]));

A test I just ran showed "id = ANY(ARRAY[1,2,3])" doing a sequential
scan whereas "id IN (1,2,3)" did an index scan, so you might want to
use the latter if possible.

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

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Re: [GENERAL] Turning a subselect into an array

comp.databases.postgresql.docs comp.databases.postgresql.docs

Re: [GENERAL] Turning a subselect into an array - 10-30-2004 , 01:07 AM