使用Sean Lahman数据库在MySQL中联接多个表

Question

我使用的是Sean Lahman的棒球数据库，试图返回一张球员表，其中列出了曾参加过AllStar比赛，AllStar比赛开始以及职业生涯的总数。输入以下查询时，我在AllStar，“开始”和“游戏”列中得到的数字不正确。

SELECT p.nameFirst AS FirstName, p.nameLast as LastName, COUNT(a.gameNum) as AllStar, count(a.startingPOS) as Starts, sum(e.G_all) as Games
FROM People p
    INNER JOIN AllstarFull a ON p.playerID = a.playerID
    INNER JOIN Appearances e ON p.playerID = e.playerID
GROUP BY p.playerID
ORDER BY 3 desc;