MySQL:如何合并三个表

Question

我有一个包含人员的表(personid，name)，另一个包含营地的表(campid，title)和第三个包含营地参与的表(id，personid，campid)。

现在，对于给定的营地，我需要一份包含当前营地所有参与者的所有其他营地的列表。

但我不知道如何连接这些表。我看过很多其他例子，但我似乎无法真正从这些例子中获得任何灵感......

Answer 1

这应该有效:

SELECT *
FROM PERSONS AS D INNER JOIN CAMP_PARTICIPATIONS AS E ON D.PERSONID = E.PERSONID
                  INNER JOIN CAMPS AS F ON F.CAMPID = E.CAMPID
WHERE F.CAMPID <> [your_camp]  AND A.PERSONID IN (

SELECT A.PERSONID
FROM PERSONS AS A INNER JOIN CAMP_PARTICIPATIONS AS B ON A.PERSONID = B.PERSONID
                  INNER JOIN CAMPS AS C ON C.CAMPID = B.CAMPID
WHERE C.CAMPID = [your_camp] )