In case you have your own slow SQL query, you can optimize it automatically here.
For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:
ALTER TABLE `cities` ADD INDEX `cities_idx_idcity` (`idCity`);
SELECT
m.nameMarket nm,
m.idCity idc,
c.cityname cn
FROM
markets m
LEFT JOIN
cities c
ON m.idCity = c.idCity