Demonstrate mastery of Aggregate functions, grouping, and SQL joins. /* Use the Murach AP database to produce the requested result sets. 4. Write a query that returns the total amount invoiced for each Account. 5. Write a query that calculates the number of invoices and the average invoice amount for the vendors in California. 6. Write a query that returns the Sum of the Invoice Totals for Each Vendor 7. Write a query that returns the Average of Invoice Totals for all invoices ordered by region of vendor. */