2多對多關系-通過聯接提取數據

Question

請檢查以下鏈接中的架構。

http://s11.postimg.org/dydr5ru3n/stack.png

我要選擇所有屬性，還要選擇每個屬性的代理和所有者。 問題在於代理人和所有者的詳細信息都來自同一張表，並且存在沖突。

我應該遵循什么解決方案？

注意：不幸的是，我無法更改數據庫模式。

Answer 1

SELECT oPers.first_name AS ownerFirstName
    , aPers.first_name AS agentFirstName
    ....
FROM properties AS p
LEFT JOIN owners AS po ON p.property_id = po.property_id
LEFT JOIN people AS oPers ON po.person_id = oPers.person_id
LEFT JOIN agents AS pa ON p.property_id = pa.property_id
LEFT JOIN people AS aPers ON pa.person_id = aPers.person_id
;