SELECT
city.id,
city.name,
country.name,
salary,
country.is_here
FROM city
LEFT JOIN country ON city.cid = country.id
union all
SELECT
city.id,
city.name,
country.name,
salary + 2000,
1
FROM city
LEFT JOIN country ON city.cid = country.id
where (country.id is null or country.is_here = 0)