MY SQL JOIN

select city.name

from city

join country on city.countrycode = country.code

where country.continent = 'Africa';

SELECT C.NAME FROM CITY C JOIN COUNTRY CTR ON C.COUNTRYCODE = CTR.CODE WHERE CONTINENT = 'AFRICA';

Select city.name from city join country on city.countrycode = country.code where country.continent ='Africa';

select c.name from city As c inner join country As t on c.countrycode=t.code AND t.continent="Africa";

SELECT city.district FROM CITY INNER JOIN COUNTRY ON CITY.CountryCode=COUNTRY.Code WHERE continent = "Africa";

What's wrong with my query?