sql - Pset7 - 电影卡在 12 和 13 SQL 上？

Question

我目前正在研究 CS50 PSET7 ( https://cs50.harvard.edu/x/2020/psets/7/movies/ )，但我不知道如何执行 12.sql 和 13.sql(在链接中解释)。有人可以帮助我吗？

Answer 1

对于 12.sql:在“Johnny Depp 电影的 id”中的“id”和“Helena Bonham Carter 电影的 id”中的“id”中查找电影标题，例如:

SELECT "title" FROM "movies" 
WHERE "id" IN (-- code to select movie id's in which "Johnny Depp" starred)
AND "id" IN (-- code to select movie id's in which "Helena Bonham Carter" starred);

对于13.sql:查找“stars”中的“person_id's”对应于“Kevin Bacon (born: 1958)”出演的“movie_id”且names != "Kevin Bacon"的人名，例如:

SELECT "name" FROM "people"
WHERE "id" IN 
(-- select "person id's" from "stars" where "movie id" in
(-- select "movie id's" in which "Kevin Bacon (born: 1958)" starred))
AND "name" != "Kevin Bacon";

在13.sql的第二个括号内，查询“Kevin Bacon born in 1958”，可以这样写代码:

... WHERE "people"."name" = "Kevin Bacon" AND "people"."birth" = 1958))...

想简单，不需要做任何花哨的事情。