u are working with a database table that contains invoice data. the table includes columns for billing state, billing country, and total. you want to know the average total price for the invoices billed to the state of wisconsin. you decide to use the avg function to find the average total, and use the as command to store the result in a new column called average total. add a statement to your sql query that calculates the average total and stores it in a new column as average total.