รหัสอาหาร S/ ย่อมาจากอะไรไม่จำเป็นต้องใช้ทุกโต๊ะ
what does the meal code S/ stand forIt is not neccessary to use all the tables.
 airport:  airport_code [ varchar]  airport_name [ text]  airport_location [ text]  state_code [ varchar]  country_name [ varchar]  time_zone_code [ varchar]  minimum_connect_time [ int] 
SELECT DISTINCT compartment, meal_code, meal_description, meal_number FROM food_service WHERE meal_code = 'S/'