Question

我有以下表格：

电影：

+----------+--------------+
| movie_id |     title    |
+----------+--------------+
|    1     | Wonder Woman |
+----------+--------------+

演员：

+----------+--------------+
| id       |     name     |
+----------+--------------+
|    1     |   Gal Gadot  |
+----------+--------------+
|    2     |  Chris Pine  |
+----------+--------------+

Movie_cast：

+----------+--------------+--------------+
| id       |   movie_id   |    cast_id   |
+----------+--------------+--------------+
|    1     |       1      |       1      |
+----------+--------------+--------------+
|    2     |       1      |       2      |
+----------+--------------+--------------+

基本上，Gal Gadot和Chris Pine都是电影“神奇女侠”的一部分。

我的问题是我想找到他们都的所有电影。我不希望任何电影分别播放，只有他们两个都在铸造。

我试过这样的事情：

SELECT * FROM movies
LEFT JOIN movie_cast ON movie_cast.movie_id = movies.movie_id 
LEFT JOIN cast ON movie_cast.cast_id = cast.id
WHERE cast.id = 1 AND cast.id = 2

但结果是空的。

Answer 1

你应该用这个：

SELECT m.movie_id, m.title 
FROM movies m
INNER JOIN movie_cast mc ON mc.movie_id = m.movie_id 
WHERE mc.cast_id = 1 OR mc.cast_id = 2
GROUP BY m.movie_id, m.title
HAVING COUNT(*) = 2; -- HAVING COUNT(DISTINCT mc.cast_id) = 2; -- for unnormalized data

无需LEFT JOIN，只需要通过演员姓名找到<{1}}表格

Answer 2

您可以在FROM子句中使用子查询来缩小它们所在的电影的范围。通过将转换限制为只有它们的ID号并对其进行分组，任何具有Cast_Total为2的movie_id都将具有这两个个体主演。

SELECT m.title
FROM (SELECT movie_id, COUNT(cast_id) AS Cast_Total
      FROM movie_cast 
      WHERE cast_id IN (1, 2)
      GROUP BY movie_id) temp
LEFT JOIN movies m ON m.movie_id = temp.movie_id
WHERE temp.Cast_Total = 2

Answer 3

自我加入Movie_cast以获得两位演员的电影，然后将其加入电影。

SELECT * FROM Movies A
INNER JOIN
(SELECT DISTINCT M1.movie_id movie_id FROM Movie_cast 
M1 INNER JOIN Movie_cast M2 ON M1.movie_id = M2.movie_id
WHERE M1.cast_id = 1 AND M2.cast_id = 2) B
ON A.movie_id = B.movie_id

通用版，获取丢失演员的电影（说表A）。使用此套装A连接主要电影并过滤掉丢失演员阵容的电影。

SELECT * FROM Movies A
LEFT OUTER JOIN
(
SELECT DISTINCT movie_id movie_id 
FROM Movie_cast M1 WHERE NOT EXISTS (SELECT 1 FROM Cast WHERE Id = M1.cast_id) 
) B ON A.Id = B.movie_id
WHERE B.movie_id IS NULL

LEFT JOIN与WHERE和AND参数

3 个答案: