pls step step solution

5. Write a stored function to find how much a given stock group (STOCK GROUP CODE) was sold between two dates given in terms of money (15 points) QUESTIONS CITY(CITY_CODE SMALLINT, CITY_NAME NVARCHAR(30)) CUSTOMER(C_CODE NVARCHAR(20), C_NAME NVARCHAR(30), C_LASTNAME NVACHAR(30), BIRTH_DATE DATE, PHONE NUMBER CHAR(11), GROUP_CODE NVARCHAR(20), CITY_CODE SMALLINT) STOCK(STOCK_CODE NVARCHAR(20), STOCK_NAME NVARCHAR(50), PRICE NUMERIC(10,2), STOCK_GROUP_CODE NVARCHAR(20) CUSTOMER_ACCOUNT(ID BIGINT, C_CODE NVARCHAR(20), OPERATION_DATE DATE, STOCK_CODE NVARCHAR(20), QUANTITY NUMERIC (5), PRICE NUMERIC(10,2), DEBT NUMERIC (10,2), RECEIVABLE NUMERIC(10,2), COMMENT NVARCHAR(50)) CUSTOMER ACCOUNT STOCK SOCK CODE STOCKA NOCE OOK GROW..Coor CODE ORARON DATE STOCKCOD QUANTITY PECE DET RECEMBLE COMLINE CITY CITY.CODE CITY NA CUSTOMER C.CODE CNAME CLAST STUDAT PHONE NUMBER GROUP_COOL CITY_CODE