The management is curious about how certain changes in the purchase process at WORMS may have affected sales. For all purchases made on or after May 1, 2018, management wants to see how the quantity of each buyer's purchase compares with the average quantity of that buyer's purchase from before May 1, 2018. Write a query to display the buyer number, purchase date, purchase quantity, the pre-May average purchase quantity, and the amount the current purchase differs from the pre-May average quantity for purchase made on or after May 1, 2018 by each buyer. The pre- May average is the average of the purchase quantities for all purchases made by that buyer wwith a purchase date that is before May 1, 2018. Sort the output by the buyer number and then by The purchase date. MATERIAL DEPOSIT SITE PK Dep ID Site Num Mat ID --- Dep Date > LH--- Mat_Name Mat_Type Mat_aty Mat_Price Dep Cty FK1 Mat_ID FK2site_Num Site Name Site Street Site_City Site State Site Up BUYER PURCHASE PK Buyer Num Purch_Num ----- - Purch_Date > Purch Oty Purch Price Mat_ID Buyer Num Buyer_Company Buyer_FName Buyer_LName Buyer_AreaCode Buyer Phone FK1 The management is curious about how certain changes in the purchase process at WORMS may have affected sales. For all purchases made on or after May 1, 2018, management wants to see how the quantity of each buyer's purchase compares with the average quantity of that buyer's purchase from before May 1, 2018. Write a query to display the buyer number, purchase date, purchase quantity, the pre-May average purchase quantity, and the amount the current purchase differs from the pre-May average quantity for purchase made on or after May 1, 2018 by each buyer. The pre- May average is the average of the purchase quantities for all purchases made by that buyer wwith a purchase date that is before May 1, 2018. Sort the output by the buyer number and then by The purchase date. MATERIAL DEPOSIT SITE PK Dep ID Site Num Mat ID --- Dep Date > LH--- Mat_Name Mat_Type Mat_aty Mat_Price Dep Cty FK1 Mat_ID FK2site_Num Site Name Site Street Site_City Site State Site Up BUYER PURCHASE PK Buyer Num Purch_Num ----- - Purch_Date > Purch Oty Purch Price Mat_ID Buyer Num Buyer_Company Buyer_FName Buyer_LName Buyer_AreaCode Buyer Phone FK1