I'm having some problems with INTERSECT command. Hope someone could help me.
I want to get the the movieid that appears in the first and second SELECT. After that I want to use these data (that could be in a LIMIT of 10) to receive the titles of the movie in another table.
Something like this, but I'm not doing right:
SELECT movieid
FROM ratings
WHERE votes > 0
INTERSECT SELECT movieid FROM genres WHERE genre = '$_SESSION[genero]'
In this case I should get the movied that appear both on ratings and genres tables.
After this, I want to get these movieids and search the table movies for the movieid and finally show the title. Thank you!
As far as I understood the question, I think this is what you are looking for
select title , movieid from movies
where movieid in
(
SELECT movieid FROM ratings
WHERE votes > 0
INTERSECT
SELECT movieid FROM genres
WHERE genre = '$_SESSION[genero]'
)
select distinct m.title , movieid
from
movies m
inner join
ratings r using (movieid)
inner join
genres g using (movieid)
where r.votes > 0 and g.genre = '$_SESSION[genero]'
Related
Im working on a movie data set that has tables for movies, genre and a bridge table in_genre.
The following query tries to find common genres between two movies. Im doing two joins to get the genre list and a intersect to find common genres.
Is there a more efficient way?
Table schema:
movie : movie_id(PK)(int)
in_genre(bridge_table): movie_id(FK)(int), genre_id(int)
SELECT count(*) as common_genre
FROM(
// getting genres of first movie
SELECT in_genre.genre_id
FROM movie INNER JOIN in_genre ON movie.id = in_genre.movie_id
WHERE movie.id = 0109830
INTERSECT
// getting genres of second movie
SELECT in_genre.genre_id
FROM movie INNER JOIN in_genre ON movie.id = in_genre.movie_id
WHERE movie.id = 1375666
) as genres
If it only needs the data from in_genre then there's no need to join the movie table.
And you can use an EXISTS to find the common genres.
SELECT COUNT(DISTINCT genre_id) as common_genre
FROM in_genre ig
WHERE movie_id = 0109830
AND EXISTS
(
SELECT 1
FROM in_genre ig2
WHERE ig2.movie_id = 1375666
AND ig2.genre_id = ig.genre_id
)
If you want the genres, I would simply do:
SELECT genre_id as common_genre
FROM in_genre ig
WHERE movie_id IN (0109830, 1375666)
GROUP BY genre_id
HAVING COUNT(*) = 2;
If you want the count, a subquery is simple enough:
SELECT COUNT(*)
FROM (SELECT genre_id as common_genre
FROM in_genre ig
WHERE movie_id IN (0109830, 1375666)
GROUP BY genre_id
HAVING COUNT(*) = 2
) g;
If you want full information about the genres, then I would suggest exists:
select g.*
from genres g
where exists (select 1
from in_genre ig
where ig.genre_id = g.genre_id and ig.movie_id = 0109830
) and
exists (select 1
from in_genre ig
where ig.genre_id = g.genre_id and ig.movie_id = 1375666
);
My school task was to get names from my movie database actors which play in movies with highest ratings
I made it this way and it works :
select name,surname
from actor
where ACTORID in(
select actorid
from actor_movie
where MOVIEID in (
select movieid
from movie
where RATINGID in (
select ratingid
from rating
where PERCENT_CSFD = (
select max(percent_csfd)
from rating
)
)
)
);
the output is :
Gary Oldman
Sigourney Weaver
...but I'd like to also add to this select mentioned movie and its rating. It accessible in inner selects but I don't know how to join it with outer select in which i can work just with rows found in Actor Table.
Thank you for your answers.
You just need to join the tables properly. Afterwards you can simply add the columns you´d like to select. The final select could be looking like this.
select ac.name, ac.surname, -- go on selecting from the different tables
from actor ac
inner join actor_movie amo
on amo.actorid = ac.actorid
inner join movie mo
on amo.movieid = mo.movieid
inner join rating ra
on ra.ratingid = mo.ratingid
where ra.PERCENT_CSFD =
(select max(percent_csfd)
from rating)
A way to get your result with a slightly different method could be something like:
select *
from
(
select name, surname, percent_csfd, row_number() over ( order by percent_csfd desc) as rank
from actor
inner join actor_movie
using (actorId)
inner join movie
using (movieId)
inner join rating
using(ratingId)
(
where rank = 1
This uses row_number to evaluate the "rank" of the movie(s) and then filter for the movie(s) with the highest rating.
the question is to select actors that played 2 or more distinct roles in the same movie.
And I got 3 table, actor (id,name) movie (id,name) and casts(aid,mid，role) (aid is the actor id and mid is the movie id)
I wrote a query like this
select a.name
from actor a, movie m, casts c
where a.id = c.aid and m.id = casts.mid
group by (m.name)
having count(distinct role) > 2;
this didnt print the right result and I didnt see the problem with it.
Thanks for the help!
How about this? Was there any error trying to execute your query?
select actor.name from actor, casts, movie
where casts.aid =actor.id
and casts.mid = movie.id
group by movie.name, actor.name
having count(distinct role) >= 2
As the casts table appears to contain one row per actor, movie, and role (unless you are leaving out other columns), any time a single pair of unique values of aid and mid appears on more than one row, it means the actor played more than one role in that movie. Thus, there is no reason to use distinct. Also because your desired result doesn't contain the movie names, your query doesn't need and shouldn't use the movie table.
If it is true that the cast table has only one row for each unique combination of (aid, mid, and role) then the following should work:
select name
from actor
where id in ( select aid
from casts
group by aid, mid
having count(*) > 1)
I've got 3 tables: Movies, Actors, and MovieActors. MovieActors is a many-to-many relationship of Movies and Actors with columns MovieActorId, MovieId, and ActorId
How do I find movies that have a certain set of actors in it? For example I want to find all movies that have both Michael Fassbender (actor Id 1) and Brad Pitt (actor Id 2) in them. What would the query look like?
One way is to join the tables. Filter for the actors and then insure the count has the number of actors you want in it (2 in this case)
SELECT
m.MovieID
FROM
Movies m
INNER JOIN MovieActors ma
ON m.MovieID = ma.MovieID
WHERE
ma.ActorID IN (1,2)
GROUP BY
m.MovieID
HAVING COUNT(DISTINCT ma.ActorID) = 2
DEMO
Note
Thanks to user814064 for pointing out that since Actors can have more than one role on a movie we need to count the DISTINCT ma.ActorID not just * The SQL Fiddle Demo demonstrates the difference
select m.movieid
from movies m
inner join movieactors ma on ma.movieid = m.movieid
where ma.actorid in (1,2)
group by m.movieid
having count(distinct ma.actorid) = 2
To keep it simple, you can just do two in clauses:
select * from Movies m
where m.MovieId in (select MovieId from MovieActors where ActorId = 1)
and m.MovieId in (select MovieId from MovieActors where ActorId = 2)
Performance may not be as good as a single join, but it's clean and easy to read.
i want help how to solve this sql problem.
suppose i have 3 tables
Movie
ID
Name
Genre
ID
Name
Movie_Genre (this one is the link for many to many)
FK_MovieID
FK_GenreID
i want to select all the movies that are of genre 1 and genre 3
how is this possible?
i can only select the movies of 1 genre but not the movies that are of 2 genres using
SELECT Movie.ID, Movie.Name
FROM Movies
INNER JOIN Movie_Genre ON Movie_Genre.FK_MovieID=Movie.ID
AND Movie_Genre.FK_GenreID = 1
Use:
SELECT m.id,
m.name
FROM MOVIE m
JOIN MOVIE_GENRE mg ON mg.fk_movieid = m.id
AND mg.fk_genreid IN (1, 3)
GROUP BY m.id, m.name
HAVING COUNT(DISTINCT mg.fk_genreid) = 2
The last line is key to getting rows from both genre's - the DISTINCT means duplicate associations (IE: two instances of genre 1) will be ignored because they are false positives. But the count must equal the number of genres you are looking for.
But COUNT(DISINCT isn't supported by all databases. You should mention what you are using - if not by tag, then in the question... If the primary key for the MOVIE_GENRE table is both fk_movieid and fk_genreid, then it's not an issue. Next best thing would be that both the columns are in a unique constraint/index...