-- *** before: ***
-- every vendor marked the optional side its own way
SELECT country.Name, city.Name
FROM country, city
WHERE country.Capital = city.ID(+)   -- Oracle
-- WHERE country.Capital *= city.ID  -- SQL Server

-- *** in version 92: ***
SELECT country.Name, city.Name
FROM country
LEFT OUTER JOIN city ON country.Capital = city.ID

-- Support: LEFT and RIGHT OUTER JOIN work everywhere, Access included.
-- FULL OUTER JOIN: PostgreSQL, Oracle, MS SQL Server, Firebird and
-- SQLite since 3.39 (2022); MySQL and Access still have none, there it
-- is emulated by LEFT JOIN UNION RIGHT JOIN.