MySQL Query: display the number of posts for each unique city

I'm 开发者_如何学Gonot very good at database queries. Need help with what is probably a simple query.

Database: MYSQL

zipcodes [table]

zip | city | state

post [table]

post_id | title | post | zip

I need to display the number of posts for each unique city.

---

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

---

I would do it this way. This would display the city name in the output and also show teh cities for which there are no posts exist.

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