MySQL

Question

List all the actors who made a film during the 1950s and also in the 1980s.

当我独家尝试时：

SELECT a.name
FROM movies AS m
JOIN castings AS c
JOIN actors AS a
ON m.id = c.movieid
AND c.actorid = a.id
WHERE (m.yr BETWEEN 1950 AND 1959)

或：

SELECT a.name
FROM movies AS m
JOIN castings AS c
JOIN actors AS a
ON m.id = c.movieid
AND c.actorid = a.id
WHERE (m.yr BETWEEN 1980 AND 1989)

我得到了两个单独查询的结果。但是，当我组合这些时，我没有得到任何行。

SELECT a.name
FROM movies AS m1
JOIN movies AS m2
JOIN castings AS c
JOIN actors AS a
ON m1.id = c.movieid
AND m2.id = c.movieid
AND c.actorid = a.id
AND m1.id < m2.id
WHERE (m1.yr BETWEEN 1950 AND 1959) AND (m2.yr BETWEEN 1980 AND 1989);

我怎样才能找到我要找的名字？

Answer 1

从您现有的查询开始，一种直接的方法是使用聚合，并使用 HAVING 子句进行过滤：

SELECT a.name
FROM movies AS m
JOIN castings AS c ON m.id = c.movieid
JOIN actors AS a ON c.actorid = a.id
GROUP BY a.id, a.name
HAVING 
    MAX(m.yr BETWEEN 1950 AND 1959) = 1 
    AND MAX(m.yr BETWEEN 1980 AND 1989) = 1

Answer 2

您可以在 where 子句中使用子查询。

SELECT 
    a.name 
FROM
    actors AS a 
WHERE EXISTS 
    (SELECT 
        1 
    FROM
        movies m,
        castings c 
    WHERE c.actorid = a.id 
        AND m.id = c.movieid 
        AND (m.yr BETWEEN 1950 
            AND 1959) 
    LIMIT 1) 
    OR EXISTS
    (SELECT 
        1 
    FROM
        movies m,
        castings c 
    WHERE c.actorid = a.id 
        AND m.id = c.movieid 
        AND (m.yr BETWEEN 1980 
            AND 1989) 
    LIMIT 1)

或者您可以在获取电影数量时像下面这样使用分组依据：

SELECT 
    a.name,
    SUM(IF(m.yr BETWEEN 1950 AND 1959, 1, 0)) AS e1950,     -- Number of Movies in 1950s
    SUM(IF(m.yr BETWEEN 1980 AND 1989, 1, 0)) AS e1980      -- Number of Movies in 1980s
FROM movies AS m
JOIN castings AS c
JOIN actors AS a
ON m.id = c.movieid
AND c.actorid = a.id
GROUP BY a.name HAVING e1950 > 0 AND e1980 > 0;

MySQL - 联接和介于两者之间

MySQL - Joins and Between

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join

between