数据库sql习题与答案

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Question 1:Find the titles of all movies directed by Steven Spielberg.

select title from movie where director='Steven Spielberg'

Question 2:Find all years that have a movie that received a rating of 4 or 5, and sort them in increasing order.

select distinct year from movie,rating

where movie.mid=rating.mid

and stars in (4,5)

order by year

Question 3:Find the titles of all movies that have no ratings

select title from movie

where mID in

(

select mid from Movie

except

select mid from rating

)

select title from movie

except

select title from movie,rating

where movie.mid=rating.mid

Question 4:Some reviewers didn't provide a date with

their rating. Find the names of all reviewers who have

ratings with a NULL value for the date.

select name from reviewer,rating

where reviewer.rid=rating.rid

and ratingdate is null

Question 5:Write a query to return the ratings data in a more readable format: reviewer name, movie title, stars, and ratingDate. Also, sort the data, first by reviewer name, then by movie title, and lastly by number of stars.

select name,title,stars,ratingdate

from movie,rating,reviewer

where movie.mid=rating.mid

and reviewer.rid=rating.rid

order by name,title,stars

Question 6:For all cases where the same reviewer rated the same movie twice and gave it a higher rating the second time, return the reviewer's name and the title of the movie.

select name,title

from rating as F,Rating as S,Movie,Reviewer

where F.rID=S.rID

and F.mID=S.mID

and F.stars

and F.ratingDate

and F.mID=Movie.mID

and F.rID=Reviewer.rID

select name,title

from movie,reviewer,

( select r1.rid,r1.mid from rating as r1,rating as r2

where r1.rid=r2.rid and r1.mid=r2.mid

and r1.ratingdate>r2.ratingdate

and r1.stars>r2.stars) as r

where movie.mid=r.mid and reviewer.rid=r.rid

Question 7:For each movie, find the highest number of stars that movie received as a rating. Return the movie title and number of stars. Sort by movie title.

select title,MAX(stars) as max_star

from rating,Movie

where Rating.mID=Movie.mID

group by title

order by title

select title,maxrating

from movie,

(select mid,max(stars) as maxrating from rating

group by mid) as r

where movie.mid=r.mid

order by title

Question 8:For each movie, return the title and the

‘rating spread(范围)', that is, the difference between