CREATE TABLE Payments (payment_id NUMBER, booking_id NUMBER, customer_id NUMBER, payment_type_code VARCHAR2, amount_paid_in_full_yn VARCHAR2, payment_date DATETIME, amount_due NUMBER, amount_paid NUMBER)
CREATE TABLE Products_Booked (booking_id NUMBER, product_id NUMBER, returned_yn VARCHAR2, returned_late_yn VARCHAR2, booked_count NUMBER, booked_amount FLOAT)
CREATE TABLE Products_for_Hire (product_id NUMBER, product_type_code VARCHAR2, daily_hire_cost NUMBER, product_name VARCHAR2, product_description VARCHAR2)
CREATE TABLE Bookings (booking_id NUMBER, customer_id NUMBER, booking_status_code VARCHAR2, returned_damaged_yn VARCHAR2, booking_start_date DATETIME, booking_end_date DATETIME, count_hired VARCHAR2, amount_payable NUMBER, amount_of_discount NUMBER, amount_outstanding NUMBER, amount_of_refund NUMBER)
CREATE TABLE Customers (customer_id NUMBER, coupon_id NUMBER, good_or_bad_customer VARCHAR2, first_name VARCHAR2, last_name VARCHAR2, gender_mf VARCHAR2, date_became_customer DATETIME, date_last_hire DATETIME)
CREATE TABLE Discount_Coupons (coupon_id NUMBER, date_issued DATETIME, coupon_amount NUMBER)
CREATE TABLE View_Product_Availability (product_id NUMBER, booking_id NUMBER, status_date DATETIME, available_yn VARCHAR2)

Take the first name of all the good customers as the X-axis and gender of all the good customers as Y-axis in a bar chart.
SELECT first_name, gender_mf FROM Customers WHERE good_or_bad_customer = 'good'
SELECT "first_name", "gender_mf" FROM "Customers" WHERE "good_or_bad_customer" = 'good'