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.
Related
I am working on writing a sql to get the SID and SNAME. In this task, I need to count which team win the max number of League and find out the SID.
Leagues(LID, CHAMPION_TID)
LID: League ID ; CHAMPION_TID: champion team ID
SUPPORT(SID, LID)
SPONSORS(SID, SNAME)
PRIMARY KEY: LID,SID
Now, I can find out which team win the max number of League through the following SQL:
SELECT
MAX(y.cham)
FROM
(SELECT
CHAMPION_TID, COUNT(L.CHAMPION_TID) AS cham
FROM
LEAGUES L
GROUP BY
L.CHAMPION_TID) y, LEAGUES L
WHERE
y.CHAMPION_TID = L.CHAMPION_TID;
I am confusing in the following step. My idea get the LID, then use the join table to display SID and SNAME. But I suck in this step.
SELECT L.LID, MAX(y.cham)
FROM
(SELECT CHAMPION_TID, COUNT(L.CHAMPION_TID) AS cham
FROM LEAGUES L
GROUP BY L.CHAMPION_TID) y, LEAGUES L
WHERE
y.CHAMPION_TID = L.CHAMPION_TID
You can use the following to find the Sponsor ID and Sponsor Name:
SELECT DISTINCT
sp.SID,
sp.SNAME
FROM
LEAGUES l3
INNER JOIN support s ON
l3.LID = s.LID
INNER JOIN SPONSORS sp ON
s.SID = sp.SID
WHERE
l3.CHAMPION_TID IN (
SELECT
l2.CHAMPION_TID
FROM
LEAGUES l2
GROUP BY
l2.CHAMPION_TID
HAVING
count(l2.CHAMPION_TID) = (
SELECT
count(l1.CHAMPION_TID)
FROM
LEAGUES l1
GROUP BY
l1.CHAMPION_TID
ORDER BY
count(l1.CHAMPION_TID) DESC
FETCH FIRST 1 ROW ONLY
)
);
It finds the count of CHAMPION_TID in LEAGUES, orders it by desc (such that the highest count is always on top), then uses it to find the associated CHAMPION_TID. It handles ties for max(count(CHAMPION_TID)) as well :)
If fetch first 1 row only does not work, you can use select top 1 l1.CHAMPION_TID...
Here is a working demo using Postgres.
Lets say i've got a db with 3 tables:
Players (PK id_player, name...),
Tournaments (PK id_tournament, name...),
Game (PK id_turn, FK id_tournament, FK id_player and score)
Players participate in tournaments. Table called Game keeps track of each player's score for different tournaments)
I want to create a view that looks like this:
torunament_name Winner highest_score
Tournament_1 Jones 300
Tournament_2 White 250
I tried different aproaches but I'm fairly new to sql (and alsoto this forum)
I tried using union all clause like:
select * from (select "Id_player", avg("score") as "Score" from
"Game" where "Id_tournament" = '1' group by "Id_player" order by
"Score" desc) where rownum <= 1
union all
select * from (select "Id_player", avg("score") as "Score" from
"Game" where "Id_tournament" = '2' group by "Id_player" order by
"Score" desc) where rownum <= 1;
and ofc it works but whenever a tournament happens, i would have to manually add a select statement to this with Id_torunament = nextvalue
EDIT:
So lets say that player with id 1 scored 50 points in tournament a, player 2 scored 40 points, player 1 wins, so the table should show only player 1 as the winner (or if its possible 2or more players if its a tie) of this tournament. Next row shows the winner of second tournament. I dont think Im going to put multiple games for one player in the same tournament, but if i would, it would probably count avg from all his scores.
EDIT2:
Create table scripts:
create table players
(id_player numeric(5) constraint pk_id_player primary key, name
varchar2(50));
create table tournaments
(id_tournament numeric(5) constraint pk_id_tournament primary key,
name varchar2(50));
create table game
(id_game numeric(5) constraint pk_game primary key, id_player
numeric(5) constraint fk_id_player references players(id_player),
id_tournament numeric(5) constraint fk_id_tournament references
tournaments(id_tournament), score numeric(3));
RDBM screenshot
FINAL EDIT:
Ok, in case anyone is wondering I used Jorge Campos script, changed it a bit and it works. Thank you all for helping. Unfortunately I cannot upvote comments yet, so I can only thank by posting. Heres the final script:
select
t.name,
p.name as winner,
g.score
from
game g inner join tournaments t
on g.id_tournament = t.id_tournament
inner join players p
on g.id_player = p.id_player
inner join
(select g.id_tournament, g.id_player,
row_number() over (partition by t.name order by
score desc) as rd from game g join tournaments t on
g.id_tournament = t.id_tournament
) a
on g.id_player = a.id_player
and g.id_tournament = a.id_tournament
and a.rd=1
order by t.name, g.score desc;
This query could be simplified depending on the RDBMs you are using.
select
t.name,
p.name as winner,
g.score
from
game g inner join tournaments t
on g.id_tournament = t.id_tournament
inner join players p
on g.id_player = p.id_player
inner join
(select id_tournament,
id_player,
row_number() over (partition by t.name order by score desc) as rd
from game
) a
on g.id_player = a.id_player
and g.id_tournament = a.id_tournament
and a.rd=1
order by t.name, g.score desc
Assuming what you want as "Display high score of each player in each tournament"
your query would be like below in MS Sql server
select
t.name as tournament_name,
p.name as Winner,
Max(g.score) as [Highest_Score]
from Tournmanents t
Inner join Game g on t.id_tournament=g.id_tournament
inner join Players p on p.id_player=g.id_player
group by
g.id_tournament,
g.id_player,
t.name,
p.name
Please check this if this works for you
SELECT tournemntData.id_tournament ,
tournemntData.name ,
dbo.Players.name ,
tournemntData.Score
FROM dbo.Game
INNER JOIN ( SELECT dbo.Tournaments.id_tournament ,
dbo.Tournaments.name ,
MAX(dbo.Game.score) AS Score
FROM dbo.Game
INNER JOIN dbo.Tournaments ONTournaments.id_tournament = Game.id_tournament
INNER JOIN dbo.Players ON Players.id_player = Game.id_player
GROUP BY dbo.Tournaments.id_tournament ,
dbo.Tournaments.name
) tournemntData ON tournemntData.id_tournament =Game.id_tournament
INNER JOIN dbo.Players ON Players.id_player = Game.id_player
WHERE tournemntData.Score = dbo.Game.score
Database Structure
MovieInfo (mvID, title, rating, year, length, studio)
DirectorInfo(directorID, firstname, lastname)
MemberInfo(username, email, password)
ActorInfo(actorID, firstname, lastname, gender, birthplace)
CastInfo(mvID*, actorID*)
DirectInfo(mvID*, directorID*)
GenreInfo(mvID*, genre)
RankingInfo(username*, mvID*, score, voteDate)
Query
I need to get the director with the largest number of comedy movies. (I'm also required to use the ALL operator). My understanding is getting the list of mvid where genre = 'Comedy" and directorid:
select mvid
from genreinfo
where genre = 'Comedy'
union all
select directorid
from directorinfo
;
But then how do I count the number of movies a specific director has? And how do I get that single one with the highest count of "comedy" movies?
You're on the right track. I'd recommend looking at JOINs.
I've provided a step-by-step answer on how to obtain the desired results. If you just want the final query, go down to step 5 and pick the one appropriate for your DBMS.
1: Selecting all comedy movie IDs:
SELECT mvid
FROM GenreInfo
WHERE genre = 'Comedy';
2: Selecting the directorIDs of those movies
SELECT directorID
FROM DirectInfo
JOIN GenreInfo
ON DirectInfo.mvID = GenreInfo.mvID
WHERE genre = 'Comedy';
3: Selecting the director name of those directors.
SELECT firstname
FROM DirectorInfo
JOIN DirectInfo
ON DirectorInfo.directorID = DirectInfo.directorID
JOIN GenreInfo
ON DirectInfo.mvID = GenreInfo.mvID
WHERE genre = 'Comedy';
4: Grouping that query by director to get number of movies:
SELECT firstname, COUNT(*) AS NumberOfMovies
FROM DirectorInfo
JOIN DirectInfo
ON DirectorInfo.directorID = DirectInfo.directorID
JOIN GenreInfo
ON DirectInfo.mvID = GenreInfo.mvID
WHERE genre = 'Comedy'
GROUP BY DirectorInfo.directorID;
5: Sort the results and get only the first one:
SELECT firstname, COUNT(*) AS NumberOfMovies
FROM DirectorInfo
JOIN DirectInfo
ON DirectorInfo.directorID = DirectInfo.directorID
JOIN GenreInfo
ON DirectInfo.mvID = GenreInfo.mvID
WHERE genre = 'Comedy'
GROUP BY DirectorInfo.directorID
ORDER BY NumberOfMovies
LIMIT 1;
If you're using SQL server, use TOP instead:
SELECT TOP 1 firstname, COUNT(*) AS NumberOfMovies
FROM DirectorInfo
JOIN DirectInfo
ON DirectorInfo.directorID = DirectInfo.directorID
JOIN GenreInfo
ON DirectInfo.mvID = GenreInfo.mvID
WHERE genre = 'Comedy'
GROUP BY DirectorInfo.directorID
ORDER BY NumberOfMovies;
You can use a join and group by to get the result.
select DirectorID,COUNT(mvid)
from DirectInfo d
inner join genreinfo g
ON d.mvid=g.mvid
where genre ='Comedy'
GROUP BY DirectorID
ORDER BY COUNT(mvid)
This is homework? Well, right now you are selecting a list of IDs, some of them representing directors, others representing movies. You notice that this is not at all what you are supposed to do, right?
What you want is a list of directors. So you select from the DirectorInfo table. You also want information about his movies (excatly: the number of movies of a certain kind). So you must join that information from MovieInfo. Now think about what else you need to glue together to get from director to their movies. Then think about how to glue in that genre criterium.
Once you have joined it all together, then you group your results. You want one record per director (instead of ane record per director and movie), so you make a group and count within that group.
I hope this helps you solve your task. Good luck!
select di.directorid, count(1) as 'no_of_comedy_movies'
from DirectorInfo di inner join join DirectInfo dri
on di.directorid = dri.directorid
inner join genreinfo gi
on gi.mvid = dri.mvid
where gi.genre = 'Comedy'
group by dri.directorID
order by no_of_comedy_movies
I spent a lot of time building this select, but Im not able to solve it. I have 2 tables. First table is called car and has PK (primary key) id_car and another columns name and so on. Second table is called rating and has colums id_rating (PK), id_car (FK) and rating_value (integer). As you suspect, one car can have more than one ranting. I want to select all cars and I want to know average rating to each car. Finally, I want to order the result by this average desc. I was trying things like this:
SELECT id_car, name, average
FROM car C, rating R
WHERE C.id_car = R.id_car
ORDER BY (average) (
SELECT AVG(rating_value) AS average
FROM rating R
WHERE C.id_car = R.id_car)
but it doesn't work.
For SQL Server; Also I suggest you to use JOIN instead of WHERE table1, table2..
SELECT C.id_car, name, AVG(rating_value) AS average
FROM car C JOIN rating R
ON C.id_car = R.id_car
GROUP By C.id_car, name
ORDER BY average DESC
This implements the aggregate function AVG() and then a GROUP BY the car id and name:
select c.id_car, c.name, avg(r.rating_value) aver
from car c
left join rating r
on c.id_car = r.id_car
group by c.id_car, c.name
order by aver desc
Using a LEFT JOIN will include all cars in the result even those which have no yet been rated.
SELECT C.name, AVG(R.rating_value)
FROM car C, rating R
WHERE C.id_car = R.id_car
GROUP BY C.name
ORDER BY AVG(R.rating_value) DESC
SELECT c.id_car, c.name,avg(r.rating_value) as rating
FROM car c
join rating r
on c.id_car = r.id_car
group by r.id_car
order by rating
Here are two table in parent/child relationship.
What i need to do is to select students with there average mark:
CREATE TABLE dbo.Students(
Id int NOT NULL,
Name varchar(15) NOT NULL,
CONSTRAINT PK_Students PRIMARY KEY CLUSTERED
(
CREATE TABLE [dbo].[Results](
Id int NOT NULL,
Subject varchar(15) NOT NULL,
Mark int NOT NULL
)
ALTER TABLE [dbo].[Results] WITH CHECK ADD CONSTRAINT [FK_Results_Students] FOREIGN KEY([Id])
REFERENCES [dbo].[Students] ([Id])
I wrote a query like this :
SELECT name , coalesce(avg(r.[mark]),0) as Avmark
FROM students s
LEFT JOIN results r ON s.[id]=r.[id]
GROUP BY s.[name]
ORDER BY ISNULL(AVG(r.[mark]),0) DESC;
But the result is that all of students with there avg mark in desc order.What i need is to restrict result set with students that have the highest average mark agaist other,i.e.if the are two students with avg mark 50 and 1 with 25 i need to display only those students with 50.If there are only one student with highest avg mark- only he must appear in result set.How can i do this in best way?
SQL Server 2005+, using CTEs:
WITH grade_average AS (
SELECT r.id,
AVG(r.mark) 'avg_mark'
FROM RESULTS r
GROUP BY r.id),
highest_average AS (
SELECT MAX(ga.avg_mark) 'highest_avg_mark'
FROM grade_average ga)
SELECT DISTINCT
s.name,
ga.avg_mark
FROM STUDENTS s
JOIN grade_average ga ON ha.id = s.id
JOIN highest_average ha ON ha.highest_avg_mark = ga.avg_mark
Non-CTE equivalent:
SELECT DISTINCT
s.name,
ga.avg_mark
FROM STUDENTS s
JOIN (SELECT r.id,
AVG(r.mark) 'avg_mark'
FROM RESULTS r
GROUP BY r.id) ga ON ha.id = s.id
JOIN SELECT MAX(ga.avg_mark) 'highest_avg_mark'
FROM (SELECT r.id,
AVG(r.mark) 'avg_mark'
FROM RESULTS r
GROUP BY r.id) ga) ha ON ha.highest_avg_mark = ga.avg_mark
If you're using a relatively new version of MS SQL server, you can use WITH to make this simple to write:
WITH T AS (
SELECT
name,
coalesce(avg(r.[mark]),0) as mark
FROM students s
LEFT JOIN results r ON s.[id]=r.[id]
GROUP BY s.[name])
SELECT name as 'ФИО', mark as 'Средний бал'
FROM T
WHERE T.mark = (SELECT MAX(mark) from T)
Is it as simple as this? For all versions of SQL Server 2000+
SELECT TOP 1 WITH TIES
name, ISNULL(avg(r.[mark]),0) as AvMark
FROM
students s
LEFT JOIN
results r ON s.[id]=r.[id]
GROUP BY
s.[name]
ORDER BY
ISNULL(avg(r.[mark]),0) DESC;
SELECT name as 'ФИО',
coalesce(avg(r.[mark]),0) as 'Средний бал'
FROM students s
LEFT JOIN results r
ON s.[id]=r.[id]
GROUP BY s.[name]
HAVING AVG(r.[mark]) >= 50
ORDER BY ISNULL(AVG(r.[mark]),0) DESC
about HAVING clause