我发现以下步骤很有帮助：
1.获取Kevin Bacon的ID，条件是Kevin Bacon出生于1958年
1.使用Kevin Bacon的ID获取他的电影ID（提示：将table1中的ID与table2链接）
1.获取具有相同电影ID的其他明星的ID
1.得到这些明星的名字，并排除凯文培根（因为规范说他不应该包括在结果列表中）
注意：在代码的第一行中，可以使用SELECT name而不是COUNT(name)来获取人员的姓名

我试着在Zara的步骤回答：

SELECT people.name
FROM people
WHERE people.id = (
    SELECT stars.person_id
    FROM stars
    JOIN movies ON stars.movie_id = movies.id
    WHERE movies.id = (
        SELECT movies.id
        FROM movies
        JOIN stars ON stars.movie_id = movies.id
        JOIN people ON stars.person_id = people.id
        WHERE people.id = (
            SELECT id
            FROM people
            WHERE birth = 1958 AND name = "Kevin Bacon")
                    )
)

结果：

我一定是做错了步骤才得到这个结果
预期176行，但只有一行“Steve gutenberg ”

我没有使用任何Join，只是嵌套了条件。

SELECT people.name FROM people
WHERE people.id IN 
(
    SELECT stars.person_id FROM stars
    WHERE stars.movie_id IN 
    (
        SELECT stars.movie_id FROM stars
        WHERE stars.person_id IN
        (
            SELECT people.id FROM people
            WHERE people.name = "Kevin Bacon" AND 
            people.birth = 1958
        )
    )
)
AND people.name != "Kevin Bacon" 
GROUP BY people.name

我还在不使用JOIN而仅使用嵌套查询的情况下解决了这个问题：

SELECT name FROM people
WHERE id IN (
    SELECT person_id FROM stars
    WHERE movie_id IN (
        SELECT movie_id FROM stars
        WHERE person_id = (
            SELECT id FROM people
            WHERE name = "Kevin Bacon" AND birth = 1958)))
EXCEPT 
    SELECT name FROM people
    WHERE name = "Kevin Bacon" and birth = 1958;

我试图避免使用嵌套查询，但实际上，如果不使用嵌套查询，我就无法进入正确的路径。
我的代码如下：
1.获取出生于1958年的Kevin Bacon的ID。（返回Kevin Bacon的ID）
1.获取凯文·培根主演的所有电影。（返回凯文·培根主演的电影列表）
1.获取与每部电影相关的所有person_id（返回每部电影的person_id列表，包括Kevin Bacon的id）
1.除了凯文·培根本人。

在自上而下的层次结构中获取值，但要确保在正确的域中搜索它。获取所需的第一项内容是名称，但要在依赖于person_id的正确域中搜索它，然后再搜索movie_id。最后，要调用条件，我们必须重新调用people.id，因为条件依赖于people表中的数据。在每一步执行所需的JOIN是必不可少的。
若要从结果中移除Kevin Bacon，您可以使用EXCEPT保留字，并在其他查询中特别选择他。

SELECT name FROM people WHERE people.id
IN
( SELECT person_id FROM stars JOIN movies ON movies.id = stars.movie_id 
WHERE movie_id IN
( SELECT movie_id FROM movies JOIN stars ON stars.movie_id = movies.id JOIN people ON 
 people.id = stars.person_id WHERE people.id IN (
SELECT id FROM people WHERE people.name = "Kevin Bacon" AND people.birth = 1958 )))
EXCEPT
SELECT name FROM people WHERE people.name = "Kevin Bacon" AND people.birth = 1958

我通过在SQL中使用DISTINCT和NOT EQUAL运算符解决了这个问题。
以下是我采取的步骤：

SELECT DISTINCT(name)
FROM people
JOIN stars ON stars.person_id = people.id
JOIN movies ON movies.id = stars.movie_id
WHERE movies.id IN
    (SELECT movie_id
     FROM movies
     JOIN stars ON stars.movie_id = movies.id
     JOIN people ON people.id = stars.person_id
     WHERE people.name = "Kevin Bacon"
       AND people.birth = 1958)
  AND people.name != "Kevin Bacon";

结果是176行不同的名称。