Aliases

The outputs of the last two tasks were single columns with single values. If you noticed, this column had a name count, which is not, to be honest representative. Seems like it's only a matter of taste. But in the future, when you will work with multiple tables, will join one table to another, the same names will be a huge problem. Even from the point of interpreting the data.

In SQL you can easily declare a new name to a column by using AS statement. For example,

This query will return a single value in the single column named number of countries, which is much readable than count.

Please note, that the aliases you use must be placed within double-quotes. Using single quotes will result in SQL error!