mysql查询计划是什么

SELECT city.name AS 'City',

               country.name AS 'Country'

FROM city

JOIN country ON (city.countrycode = country.code)

WHERE country.code = 'GBR'

LIMIT 5;

SELECT `world`.`city`.`Name` AS `City`,

                'United Kingdom' AS `Country`

FROM `world`.`city`

JOIN `world`.`country`

WHERE (`world`.`city`.`CountryCode` = 'GBR')

LIMIT 5;