Mysql 选择三个表并计数

我有三个表，我需要选择email并计算表A和表B之间的关系，例如：

表A：

 ID   |  email
 1    |  test@test
 2    |  test2@test
 3    |  test3@test

表B：

UID   | username
11    | James
22    | Gabriel
33    | Jonas

表C：（A和B之间的关系）

预期结果：

Email      | Totalrelation
test@test  | 2
test2@test | 1

我试过：

   select tableA.email, 
    COUNT(distinct tableC.email_id) AS total from tableA as tableA, tableC as tableC GROUP BY tableC.email_id

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但它不起作用，我完全错了。我该怎么做呢？

加入表格，对数据进行分组，并计算每组的数量

select a.email, count(c.id) as cnt
from tableA a
left join tableC c on c.email_id = a.id
group by a.email

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我不能这样做，因为C只有电子邮件id，A有电子邮件值

select a.email, count(c.id) as cnt
from tableA a
left join tableC c on c.email_id = a.id
group by a.email