The chinook store is set up in a way

The Chinook store is set up in a way that allows customer to make purchases in one of the two ways:

● purchase a whole album

● purchase a collection of one or more individual tracks.

The store does not let customers purchase a whole album, and then add individual tracks to that same purchase (unless

they do that by choosing each track manually). When customers purchase albums, they are charged the same price as if

they had purchased each of those tracks separately.

Management are currently considering changing their purchasing strategy to save money. The strategy they are

considering is to purchase only the most popular tracks from each album from record companies, instead of purchasing

every track from an album.

We have been asked to find out what percentage of purchases are individual tracks vs whole albums, so that

management can use this data to understand the effect this decision might have on overall revenue.

Task 3

1. Write a query that categorizes each invoice as either an album purchase or not, and calculates the following summary

Statistics:

• Number of invoices

• Percentage of invoices