According to the conceptual$/$physical model, all required is the SQL code AND two screenshots of outputs of these two queries in Oracle SQL Developer, one for Query$1$a$)$ and one for Query$1$b$),$ but since I couldn't send the data of these tables, I just want you to write the SQL code and see all the screenshots and my descriptions in this text. Please, read carefully and make sure the queries are correct and executable:

Query$1$a$)$ You need to create dimension with the following levels: Country, Manufacturer Name, Car Model; and calculate summary of rental cost for every level of dimension including grand total from all levels.

Sort results by county, then by manufacturer name, then by car model.

Query$1$b$)$ Calculate average values of rentals cost in every month, every year and average across all periods, in one query.

Sort results by year, then by month.