The Packages table represents packages that customers purchase. Each package has an ID, a start and end date (represented by a number), and a number of installs that the package includes. The Consumption table shows us how many installs each account used and when. When we get a user's consumption data, we need to check according to the date, which packages the user used. A user can only have one package at any given time. The report we need to calculate needs to show how many installs a user used from each of its packages, and how many installs remain in each package the user purchased. Packages table +-----+-------------------+----------------+-------------------+ |pack |pack_end_date |pack_installs |pack_start_date| +-----+-------------------+----------------+-------------------+ | 1 | 123460| 10| 123456| | 2 | 123470| 5| 123460| | 3 | 123475| 10| 123470| +-----+-------------------+----------------+-------------------+ consumption table +----------+--------------+---------+ |account |install_date | installs| +----------+--------------+---------+ | AB| 123459| 10| | AB| 123465| 5| | AB| 123466| 3| +----------+--------------+---------+
