You already have most of the result columns, so the following should do it.
SELECT pc.cod,
pc.val,
pi.qtd,
COALESCE(pc.name, 'empty') AS name,
lower(coalesce(pc.email, 'empty')) as email,
status,
c1.relname,
c2.relname,
pc.startdate
FROM pc
INNER JOIN pi on (pc.cod = pi.cod)
JOIN pg_class c1 ON (c1.relname = 'pc' AND c1.relkind = 'r'
JOIN pg_class c2 ON (c2.relname = 'pi' AND c2.relkind = 'r'
WHERE pc.startdate > CURRENT_DATE
order by 1 desc;
Learn the catalogs and you will learn to be a good dba.
Melvin Davidson