Add a subquery to the SELECT clause

Subqueries in SELECT statements generate a single value that allow you to pass an aggregate value down a data frame. This is useful for performing calculations on data within your database.

In the following exercise, you will construct a query that calculates the average number of goals per match in each country's league.

In the subquery, select the average total goals by adding home_goal and away_goal.
Filter the results so that only the average of goals in the 2013/2014 season is calculated.
In the main query, select the average total goals by adding home_goal and away_goal. This calculates the average goals for each league.
Filter the results in the main query the same way you filtered the subquery. Group the query by the league name.

Exercise

Add a subquery to the SELECT clause

Instructions