Postgres table size in bytes

psql_table_sizes.sql

SELECT nspname || '.' || relname AS "relation",
    pg_size_pretty(pg_relation_size(C.oid)) AS "size"
  FROM pg_class C
  LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)
  WHERE nspname NOT IN ('pg_catalog', 'information_schema')
	and nspname = 'public'
	and relkind = 'r'
  ORDER BY pg_relation_size(C.oid) DESC;