Multiple inheritance

WITH tables_in_inheritance_hierarchy AS (SELECT pn.nspname AS parent_schema, p.relname AS parent_table, pc.nspname AS child_schema, c.relname AS child_table
FROM pg_inherits pi INNER JOIN pg_class p ON pi.inhparent=p.oid
INNER JOIN pg_namespace pn ON p.relnamespace=pn.oid
INNER JOIN pg_authid AS ap ON pn.nspowner=ap.oid
INNER JOIN pg_class c ON pi.inhrelid=c.oid
INNER JOIN pg_namespace pc ON c.relnamespace=pc.oid
INNER JOIN pg_authid AS ac ON pc.nspowner=ac.oid
WHERE (pn.nspname='public' OR ap.rolname<>'postgres') 
AND (pc.nspname='public' OR ac.rolname<>'postgres'))
SELECT child_schema, child_table, string_agg(parent_schema || '.' || parent_table, ',<br>' ORDER BY parent_schema, parent_table) AS parents, Count(*) AS number_of_parents
FROM tables_in_inheritance_hierarchy
GROUP BY child_schema, child_table
HAVING Count(*)>1
ORDER BY Count(*) DESC, child_schema, child_table;