Task $3$: Query Writing $(18$ Points$)$

Write SQL queries to answer the following questions based on the $3$ tables and data that you already inserted into your DB:

Retrieve the full name $($concatenation of first name and last name$)$ of all customers.

Retrieve the products with a price higher than $$50.$

Retrieve the total quantity of each product sold.

Retrieve the orders placed on a specific date.

Retrieve the email addresses of customers who placed an order for a specific product.

Retrieve the number of orders placed by each customer.

Retrieve the total revenue generated by each customer.

Retrieve the average price of products.