SQL exercises on movie Database: Find the movie title, year, date of release, director and actor for those movies which reviewer is unknown
4. From the following tables, write a SQL query to find for movies whose reviewer is unknown. Return movie title, year, release date, director first name, last name, actor first name, last name.
Sample table: movie
mov_id | mov_title | mov_year | mov_time | mov_lang | mov_dt_rel | mov_rel_country
--------+----------------------------------------------------+----------+----------+-----------------+------------+-----------------
901 | Vertigo | 1958 | 128 | English | 1958-08-24 | UK
902 | The Innocents | 1961 | 100 | English | 1962-02-19 | SW
903 | Lawrence of Arabia | 1962 | 216 | English | 1962-12-11 | UK
904 | The Deer Hunter | 1978 | 183 | English | 1979-03-08 | UK
905 | Amadeus | 1984 | 160 | English | 1985-01-07 | UK
906 | Blade Runner | 1982 | 117 | English | 1982-09-09 | UK
907 | Eyes Wide Shut | 1999 | 159 | English | | UK
908 | The Usual Suspects | 1995 | 106 | English | 1995-08-25 | UK
909 | Chinatown | 1974 | 130 | English | 1974-08-09 | UK
......
925 | Braveheart | 1995 | 178 | English | 1995-09-08 | UK
|Sample table: actor
act_id | act_fname | act_lname | act_gender
--------+----------------------+----------------------+------------
101 | James | Stewart | M
102 | Deborah | Kerr | F
103 | Peter | OToole | M
104 | Robert | De Niro | M
105 | F. Murray | Abraham | M
106 | Harrison | Ford | M
107 | Nicole | Kidman | F
108 | Stephen | Baldwin | M
109 | Jack | Nicholson | M
.....
124 | Ali | Astin | F
Sample table: director
dir_id | dir_fname | dir_lname
--------+----------------------+----------------------
201 | Alfred | Hitchcock
202 | Jack | Clayton
203 | David | Lean
204 | Michael | Cimino
205 | Milos | Forman
206 | Ridley | Scott
207 | Stanley | Kubrick
208 | Bryan | Singer
209 | Roman | Polanski
....
223 | Peter | Jackson
Sample table: movie_direction
dir_id | mov_id
--------+--------
201 | 901
202 | 902
203 | 903
204 | 904
205 | 905
206 | 906
207 | 907
208 | 908
209 | 909
...
221 | 923
Sample table: movie_cast
act_id | mov_id | role
--------+--------+--------------------------------
101 | 901 | John Scottie Ferguson
102 | 902 | Miss Giddens
103 | 903 | T.E. Lawrence
104 | 904 | Michael
105 | 905 | Antonio Salieri
106 | 906 | Rick Deckard
107 | 907 | Alice Harford
108 | 908 | McManus
....
119 | 919 | Alfred Borden
Sample table: reviewer
rev_id | rev_name --------+-------------------------------- 9001 | Righty Sock 9002 | Jack Malvern 9003 | Flagrant Baronessa 9004 | Alec Shaw 9005 | 9006 | Victor Woeltjen 9007 | Simon Wright 9008 | Neal Wruck 9009 | Paul Monks .... 9020 | Richard Adams
Sample table: rating
mov_id | rev_id | rev_stars | num_o_ratings
--------+--------+-----------+---------------
901 | 9001 | 8.40 | 263575
902 | 9002 | 7.90 | 20207
903 | 9003 | 8.30 | 202778
906 | 9005 | 8.20 | 484746
924 | 9006 | 7.30 |
908 | 9007 | 8.60 | 779489
909 | 9008 | | 227235
....
923 | 9020 | 6.70 | 13091
Sample Solution:
-- Selecting specific columns from various tables (movie, movie_direction, director, rating, reviewer, actor, movie_cast)
-- Using aliases (a, b, c, d, e, f, g) for better readability
SELECT mov_title, mov_year, mov_dt_rel, dir_fname, dir_lname,
act_fname, act_lname
FROM movie a, movie_direction b, director c,
rating d, reviewer e, actor f, movie_cast g
-- Joining tables based on their relationships using specified conditions
-- Combining data from multiple tables to retrieve relevant information
WHERE a.mov_id=b.mov_id
AND b.dir_id=c.dir_id
AND a.mov_id=d.mov_id
AND d.rev_id=e.rev_id
AND a.mov_id=g.mov_id
AND g.act_id=f.act_id
AND e.rev_name IS NULL;
Sample Output:
mov_title | mov_year | mov_dt_rel | dir_fname | dir_lname | act_fname | act_lname
----------------------------------------------------+----------+------------+----------------------+----------------------+----------------------+----------------------
Blade Runner | 1982 | 1982-09-09 | Ridley | Scott | Harrison | Ford
Princess Mononoke | 1997 | 2001-10-19 | Hayao | Miyazaki | Claire | Danes
(2 rows)
Code Explanation:
The said query in SQL that selects various information about movies, directors, actors, and reviewers
from several tables in the movie database, but only for movies that have not been reviewed.
This query retrieve columns movie title, year,
date of release, director first and last names, actor first and last names from the tables join together are 'movie', 'movie_direction', 'director', 'rating', 'reviewer', 'actor', and 'movie_cast'.
The JOIN clause joins the 'movie' and 'movie_direction' table on "mov_id" column the 'movie_direction' and 'director' tables on "dir_id" column, the 'movie' and 'rating' tables on "mov_id" column, the 'rating' and 'reviewer' tables on "rev_id" column the 'movie' and 'movie_cast' tables on "mov_id" column , the 'movie_cast' and 'actor' tables on "act_id" column, and the "rev_name" column in 'reviewer' must be NULL (i.e., the movie has not been reviewed).
Alternative Solutions:
Using Explicit JOIN Syntax:
SELECT a.mov_title, a.mov_year, a.mov_dt_rel,
c.dir_fname, c.dir_lname, f.act_fname, f.act_lname
FROM movie a
JOIN movie_direction b ON a.mov_id = b.mov_id
JOIN director c ON b.dir_id = c.dir_id
JOIN rating d ON a.mov_id = d.mov_id
JOIN reviewer e ON d.rev_id = e.rev_id
JOIN movie_cast g ON a.mov_id = g.mov_id
JOIN actor f ON g.act_id = f.act_id
WHERE e.rev_name IS NULL;
Explanation:
This solution uses the explicit JOIN syntax to join the necessary tables based on their respective keys. It selects the specified columns and applies the condition for rev_name being NULL.
Using INNER JOIN with ON Clause:
SELECT a.mov_title, a.mov_year, a.mov_dt_rel,
c.dir_fname, c.dir_lname, f.act_fname, f.act_lname
FROM movie a
INNER JOIN movie_direction b ON a.mov_id = b.mov_id
INNER JOIN director c ON b.dir_id = c.dir_id
INNER JOIN rating d ON a.mov_id = d.mov_id
INNER JOIN reviewer e ON d.rev_id = e.rev_id
INNER JOIN movie_cast g ON a.mov_id = g.mov_id
INNER JOIN actor f ON g.act_id = f.act_id
WHERE e.rev_name IS NULL;
Explanation:
This solution also uses the explicit JOIN syntax with the ON clause to specify the join conditions. It selects the specified columns and applies the condition for rev_name being NULL.
Relational Algebra Expression:
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