子查询有许多很棒的方法，但是看来在本教程中您仅使用JOIN。以下是仅使用JOIN的方法：
SELECT
movie.title,
a2.name
FROM
actor AS a1
JOIN casting AS c1 ON (a1.id = c1.actorid)
JOIN movie ON (c1.movieid = movie.id)
JOIN casting AS c2 ON (movie.id = c2.movieid)
JOIN actor AS a2 ON (c2.actorid = a2.id)
WHERE
a1.name = 'Julie Andrews'
AND c2.ord = 1
这将为我们提供一个表，其中包含朱莉·安德鲁斯（Julie Andrews）表演过的所有电影。我将演员和演员表分别别名为a1和c1，因为现在我们已经找到了电影列表，我们必须翻动并匹配再次靠在铸件台上。
SELECT
movie.*
FROM
actor a1
JOIN casting c1 ON (a1.id = c1.actorid)
JOIN movie ON (c1.movieid = movie.id)
WHERE
a1.name = 'Julie Andrews'
现在我们有了她演过的所有电影的列表，我们需要将其与演员表（作为c2）和演员表（作为a2）结合起来，以获得这些电影的主角列表：
SELECT
movie.title, -- we'll keep the movie title from our last query
a2.name -- and select the actor's name (from a2, which is defined below)
FROM
actor a1 -- \
JOIN casting AS c1 ON (a1.id = c1.actorid) -- )- no changes here
JOIN movie ON (c1.movieid = movie.id) -- /
JOIN casting AS c2 ON (movie.id = c2.movieid) -- join list of JA movies to the cast
JOIN actor AS a2 ON (c2.actorid = a2.id) -- join cast of JA movies to the actors
WHERE
a1.name = 'Julie Andrews' -- no changes
AND c2.ord = 1 -- only select the star of the JA film
编辑：在别名中，“ AS”关键字是可选的。我在上面插入了它，以帮助查询更有意义
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