where clause subqueries vs multiple rows results

I've a query which I'd have liked to word akin to:

SELECT guid FROM child WHERE the_fkey =
( SELECT id FROM parent WHERE name ~ 'some_regex' )
ORDER BY the_fkey, my_pkey;

I got around it by doing the SELECT id first, and then doing a SELECT
guid for each row returned, appending the results together.

Can that be done in a single query, insead of 1+n queries?

Thanks,

-JimC
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James Cloos <cloos(at)jhcloos(dot)com> OpenPGP: 0xED7DAEA6