+----+------+------+-------+
| id | code | name | price |
+----+------+------+-------+

+----+------+------+
| id | code | name |
+----+------+------+

SELECT column_name
FROM information_schema.columns
WHERE table_name = "products"
AND table_schema = "schema_a"
AND column_name NOT IN (
  SELECT GROUP_CONCAT(""", column_name, """)
  FROM information_schema.columns
  WHERE table_name = "products"
  AND table_schema = "schema_b"
);

SELECT column_name
FROM information_schema.columns
WHERE table_name = "products"
AND table_schema = "schema_a"
AND column_name NOT IN ("id", "code", "name");

SELECT t1.column_name
FROM (SELECT column_name
      FROM information_schema.columns
      WHERE table_name = "products"
        AND table_schema = "schema_a") t1
LEFT JOIN (SELECT column_name
           FROM information_schema.columns
           WHERE table_name = "products"
             AND table_schema = "schema_b") t2 ON t1.column_name = t2.column_name
WHERE t2.column_name IS NULL