PostgreSQL: Compare Two Tables in PostgreSQL

CREATE TABLE foo (
   ID INT PRIMARY KEY,
   NAME VARCHAR (50)
);

CREATE TABLE bar(
   ID INT PRIMARY KEY,
   NAME VARCHAR (50)
);

INSERT INTO foo (ID, NAME)
VALUES
   (1, 'a'),
   (2, 'b');

INSERT INTO bar (ID, NAME)
VALUES
   (1, 'a'),
   (2, 'c');

select * from foo
except
select * from bar; -- returns row present in foo and not in bar => 2,b

select * from bar
except
select * from foo; -- returns row present in bar and not in foo => 2,c

(select * from foo
except
select * from bar)
UNION
(select * from bar
except
select * from foo); -- returns union of above two query. i.e rows which are not present in other table.

SELECT
   id,
   name
FROM
   foo
FULL OUTER JOIN bar USING (id, name)
WHERE
   foo.id IS NULL
OR bar.id IS NULL;

SELECT
   COUNT (*)
FROM
   foo
FULL OUTER JOIN bar USING (id, name)
WHERE
   foo.id IS NULL
OR bar.id IS NULL;

Output:
Count
2