连接查询以获取与一列中的2个值匹配的记录

Question

So, I have a movie table (movie), a category table (cat), and their relation table (movie_cat).
The "movie" table has values

id  label     
1   Ironman   

The "cat" table has values

id  label      value
1   Genre      Action
2   Language   English

The "movie_cat" table has values

id  movie_id  cat_id
1     1           1
2     1           2

I need a query that can give me the list of movies which are in "Action" and "English" category.

Answer 1

The straight-forward approach:

select *
from movie
where id in 
  (select movie_id from movie_cat where cat_id = 
    (select id from cat where label = 'Genre' and value = 'Action'))
and id in
  (select movie_id from movie_cat where cat_id =
    (select id from cat where label = 'Language' and value = 'English'));

The aggregation approach:

select *
from movie
where id in 
(
  select movie_id
  from movie_cat 
  where cat_id in (select id from cat where (label, value) in (('Genre', 'Action'),
                                                               ('Language', 'English'))
  group by movie_id
  having count(*) = 2
);