MySQL：需要MySQL逻辑的帮助

Question

我正在尝试解决MySQL问题，但我几乎遇到了...问题是...

您要运行什么查询才能获得墨西哥所有人口超过500,000的城市？ 按总体降序排列结果。

这是我要处理的表...

我当前的代码...

SELECT cities.name, cities.population
FROM countries
LEFT JOIN cities
ON countries.id = cities.country_id
WHERE cities.population < 500000

我觉得我应该超级亲密。 有指针吗？

Answer 1

弄清楚了。 我需要的只是更多细节！

旧代码...

SELECT cities.name, cities.population
FROM countries
LEFT JOIN cities
ON countries.id = cities.country_id
WHERE cities.population < 500000

新代码...

SELECT cities.name, cities.population
FROM countries 
LEFT JOIN cities
ON countries.id = cities.country_id
WHERE countries.name = 'Mexico' AND cities.population < 500000
GROUP BY cities.name
ORDER BY cities.name DESC

Answer 2

问题出在哪里呢？ 看起来很简单...未经测试;）

选择t1.name，来自国家t0的t1.population加入t0.id = t1.country_id上的城市t1和t1.population> 500000，按t1.population desc排序