MySQL查询：显示每个独特城市的帖子数量

我不太擅长数据库查询。需要一个简单查询的帮助

数据库：MYSQL

Zipcode[表] 职位[表格]

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我需要显示每个独特城市的帖子数量。

我会这样做。这将在输出中显示城市名称，并显示不存在帖子的城市

SELECT count(*) FROM post LEFT JOIN zipcodes ON post.zip = zipcodes.zip GROUP BY city;

SELECT city,count(*) as "num_posts" FROM zipcodes LEFT JOIN post ON post.zip = zipcodes.zip GROUP BY city;

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这些桌子是你们已经有的吗？

SELECT count(*) FROM post LEFT JOIN zipcodes ON post.zip = zipcodes.zip GROUP BY city;

SELECT city,count(*) as "num_posts" FROM zipcodes LEFT JOIN post ON post.zip = zipcodes.zip GROUP BY city;