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  3. Data Manipulation in SQL

Exercise

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.

Instructions

100 XP
  • 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.