Queen Anne Curiosity Shop

O$.$ Write an SQL statement to list LastName, FirstName, and Phone of customers who have purchased an item that was supplied by a vendor with a CompanyName that begins with the letter L$.$ Use a subquery.

P$.$ Answer part O but use a join using JOIN ON syntax. What are the consequences of using $($or not using$)$ the DISTINCT keyword in this version of the query?

Q$.$ Write an SQL statement to show the sum of SubTotal for each customer. List CustomerID, LastName, FirstName, Phone, and the calculated result. Name the sum of SubTotal as SumOfSubTotal and sort the results by CustomerID, in descending order.