MySQL THAM GIA Nhiều Tham gia trên cùng một bảng?

bạn cần 2 lần tham gia riêng biệt cho mỗi quốc gia / thành phố / lãnh thổ. dưới đây là cú pháp cơ bản, bạn có thể cần thay đổi nó một chút vì tôi chưa đưa nó qua trình phân tích cú pháp:

SELECT people.first_name AS "First Name", people.last_name AS "Last Name", 
countries1.name AS "Country1", territories1.name AS "Territory1", cities1.name AS "City1", 
countries2.name AS "Country2", territories2.name AS "Territory2", cities2.name AS "City2"
FROM adb_people AS people
JOIN root_cities AS cities1 ON people.city1 = cities1.id
  AND people.city2 = cities1.id
JOIN root_territories AS territories1 ON people.prov_state1 = territories1.id
  AND people.prov_state2 = territories1.id
JOIN root_countries AS countries1 ON people.country1 = countries1.id
JOIN root_cities AS cities2 ON people.city2 = cities2.id
  AND people.city2 = cities2.id
JOIN root_territories AS territories2 ON people.prov_state2 = territories2.id
  AND people.prov_state2 = territories2.id
JOIN root_countries AS countries2 ON people.country2 = countries2.id