please solve questions 11 to 15

this is database question.

thanks

Queries in Extended Relational Algebra For these questions, assume bag semantics, and that there are no NULLs. You must use the RA notation we introduce in the relational algebra slides, and may use the following operators (including extended projection): U Hint: for these questions you will need to make use of the capabilities of extended RA, but do not forget the core RA techniques either! You will need both. 5 11. Suppose we assume that a user that reviewed a release owns that release. For each user, report the user id and the total value of game releases owned by the user. 12. [I] We are doing market research. We assume that if a user reviews a game release, they also own the platform for that release - but only one of each platform. For each country of birth, report the Per-User-Purchase (PUP) from that country. The PUP is defined as the total purchase value of platforms by users from a country, divided by the total number of users in that country. Sort the outputs from country with highest PUP, to lowest. (guidance: start by figuring out the set of platforms owned by each user, the total value purchased, and the number of users per country) 13. People like cheap things (2). Report the game title, release id, and price for the least expensive release of each game. 14. For each platform, list the game id and score of the best game from that platform. The score of a game is the average rating for that game across all users, and the best game on a platform is the game with the highest score 1. If there are several such games, list all of them