Write queries in MySql to do the following tasks: (just write the needed queries, no need for specific item name in it)

9-List purchases from a certain supplier.

10- List suppliers to which CV owes money.

11- Number of purchases this month.

12- Rental history for a specific customer.

13- Requests by a specific customer.

14- Total number of DVDs purchased.

15- Total payments collected this year.

16- Which movie was requested the most.