Notice how GROUP BY is avoided in the subquery method. When the subquery give more than one row for each entry in the main query than an ERROR will be raised. For instance you cannot get the cities name on the right column to get for instances 36 times China entry for each state. 

Subquery inside FROM

The last type of subquery you will work with is one inside of FROM.
You will use this to determine the number of languages spoken for each country, identified by the country's local name! (Note this may be different than the name field and is stored in the local_name field.)