Postgres: list columns in relation A that are not in relation B (works for tables, views, materialized views)

relation_difference.sql

WITH relations AS (SELECT
    a.attname,
    pg_catalog.format_type(a.atttypid, a.atttypmod) AS type,
    t.relname
  FROM
    pg_attribute a
    JOIN pg_class t ON a.attrelid = t.oid
    JOIN pg_namespace s ON t.relnamespace = s.oid
  WHERE
    a.attnum > 0
    AND NOT a.attisdropped
    AND s.nspname = 'public'
  ORDER BY
    a.attnum
 ) 
 SELECT attname, type FROM relations WHERE relname = 'A'
 EXCEPT 
 SELECT attname, type FROM relations WHERE relname = 'B'