SQL左联接返回NULL值

Question

我有一个包含表schedule和表teams的数据库（如下图所示）我试图在内部使用homeID和awayID schedule表可以在teams表上进行联接。...问题是它返回NULL

数据库布局

Schedule表格布局

teams表格布局

我的查询

SELECT s.*,
  t1.teamId as homeId_teamId,
  t1.teamCode as homeId_teamCode,
  t1.teamName as homeId_teamName,
  t2.teamId as visitorId_teamId,
  t2.teamCode as visitorId_teamCode,
  t2.teamName as visitorId_teamName
FROM schedule s
  LEFT JOIN teams t1 ON s.homeId = t1.teamName
  LEFT JOIN teams t2 ON s.visitorId = t2.teamName
WHERE  gameID = '1';

返回结果

有人知道为什么我要为联接获取NULL值吗？我在这里想念什么？任何帮助表示赞赏。

Answer 1

id应该和id（不是名字）一起加入：

SELECT s.*,
      t1.teamId as homeId_teamId,
      t1.teamCode as homeId_teamCode,
      t1.teamName as homeId_teamName,
      t2.teamId as visitorId_teamId,
      t2.teamCode as visitorId_teamCode,
      t2.teamName as visitorId_teamName
FROM schedule s LEFT JOIN
     teams t1
     ON s.homeId = t1.teamId LEFT JOIN
     teams t2
     ON s.visitorId = t2.teamId
WHERE s.gameID = 1;

gameID是一个整数，因此比较应该是数字，而不是字符串。

我注意到homeId和visitorId的字词不匹配teams.teamId，但是命名表明这是正确的条件。如果正确定义了外键，则类型必须匹配。