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SQL exercises on movie Database: Find the reviewer name, movie title, and number of stars for those movies which rating is the lowest one

SQL movie Database: Subquery Exercise-14 with Solution

14. From the following table, write a SQL query to find the movies with the lowest ratings. Return reviewer name, movie title, and number of stars for those movies.

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
   9010 | Mike Salvati
   9011 |
   9012 | Wesley S. Walker
   9013 | Sasha Goldshtein
   9014 | Josh Cates
   9015 | Krug Stillo
   9016 | Scott LeBrun
   9017 | Hannah Steele
   9018 | Vincent Cadena
   9019 | Brandt Sponseller
   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
    910 |   9009 |      3.00 |        195961
    911 |   9010 |      8.10 |        203875
    912 |   9011 |      8.40 |
    914 |   9013 |      7.00 |        862618
    915 |   9001 |      7.70 |        830095
    916 |   9014 |      4.00 |        642132
    925 |   9015 |      7.70 |         81328
    918 |   9016 |           |        580301
    920 |   9017 |      8.10 |        609451
    921 |   9018 |      8.00 |        667758
    922 |   9019 |      8.40 |        511613
    923 |   9020 |      6.70 |         13091
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
    910 | Boogie Nights                                      |     1997 |      155 | English         | 1998-02-16 | UK
    911 | Annie Hall                                         |     1977 |       93 | English         | 1977-04-20 | USA
    912 | Princess Mononoke                                  |     1997 |      134 | Japanese        | 2001-10-19 | UK
    913 | The Shawshank Redemption                           |     1994 |      142 | English         | 1995-02-17 | UK
    914 | American Beauty                                    |     1999 |      122 | English         |            | UK
    915 | Titanic                                            |     1997 |      194 | English         | 1998-01-23 | UK
    916 | Good Will Hunting                                  |     1997 |      126 | English         | 1998-06-03 | UK
    917 | Deliverance                                        |     1972 |      109 | English         | 1982-10-05 | UK
    918 | Trainspotting                                      |     1996 |       94 | English         | 1996-02-23 | UK
    919 | The Prestige                                       |     2006 |      130 | English         | 2006-11-10 | UK
    920 | Donnie Darko                                       |     2001 |      113 | English         |            | UK
    921 | Slumdog Millionaire                                |     2008 |      120 | English         | 2009-01-09 | UK
    922 | Aliens                                             |     1986 |      137 | English         | 1986-08-29 | UK
    923 | Beyond the Sea                                     |     2004 |      118 | English         | 2004-11-26 | UK
    924 | Avatar                                             |     2009 |      162 | English         | 2009-12-17 | UK
    926 | Seven Samurai                                      |     1954 |      207 | Japanese        | 1954-04-26 | JP
    927 | Spirited Away                                      |     2001 |      125 | Japanese        | 2003-09-12 | UK
    928 | Back to the Future                                 |     1985 |      116 | English         | 1985-12-04 | UK
    925 | Braveheart                                         |     1995 |      178 | English         | 1995-09-08 | UK

Sample Solution:

-- Selecting reviewer names, movie titles, and review stars
-- Using the 'reviewer', 'movie', and 'rating' tables
-- Filtering rows where rating.rev_stars is equal to the minimum rev_stars
-- The subquery selects the minimum rev_stars from the 'rating' table
-- Joining tables based on rev_id and mov_id to get reviewer names and movie titles
SELECT reviewer.rev_name, movie.mov_title, rating.rev_stars
FROM reviewer, movie, rating
WHERE rating.rev_stars = (
  SELECT MIN(rating.rev_stars)
  FROM rating
)
AND rating.rev_id = reviewer.rev_id
AND rating.mov_id = movie.mov_id;

Sample Output:

            rev_name            |                     mov_title                      | rev_stars
--------------------------------+----------------------------------------------------+-----------
 Paul Monks                     | Boogie Nights                                      |      3.00
(1 row)

Code Explanation:

The said query in SQL that retrieves the names of reviewers who gave the lowest rating, the titles of movies that received the lowest rating, and the lowest rating itself.
the names of reviewers, the titles of movies, and the lowest ratings given by any reviewer for any movie in a database.
The query joins the tables reviewer, movie, and rating.
The query retrieves the rev_name from the reviewer table, the mov_title from the movie table, and the rev_stars from the rating table. It uses a subquery to find the minimum value of rev_stars from the rating table. It then selects the rows from the three tables where the rev_stars equals the minimum value found in the subquery, and the rev_id and mov_id in the rating table match the corresponding values in the reviewer and movie tables.

Alternative Solutions:

Using JOIN and Subquery:


SELECT r.rev_name, m.mov_title, ra.rev_stars
FROM reviewer r
JOIN rating ra ON r.rev_id = ra.rev_id
JOIN movie m ON m.mov_id = ra.mov_id
WHERE ra.rev_stars = (
    SELECT MIN(rev_stars)
    FROM rating
);

Explanation:

This query uses JOINs to combine the reviewer, rating, and movie tables based on their respective IDs. It then applies a WHERE clause to filter for ratings that have the minimum rev_stars using a subquery.

Using INNER JOIN and Subquery:


SELECT r.rev_name, m.mov_title, ra.rev_stars
FROM reviewer r
INNER JOIN rating ra ON r.rev_id = ra.rev_id
INNER JOIN movie m ON m.mov_id = ra.mov_id
WHERE ra.rev_stars = (
    SELECT MIN(rev_stars)
    FROM rating
);

Explanation:

This query also uses INNER JOINs to combine the tables and applies a WHERE clause to filter for ratings that have the minimum rev_stars using a subquery.

Using JOINs with ON Clause:


SELECT r.rev_name, m.mov_title, ra.rev_stars
FROM reviewer r
JOIN rating ra ON r.rev_id = ra.rev_id
JOIN movie m ON m.mov_id = ra.mov_id
WHERE ra.rev_stars = (
    SELECT MIN(rev_stars)
    FROM rating
);

Explanation:

This query explicitly specifies the join conditions using the ON clause. It then applies a WHERE clause to filter for ratings that have the minimum rev_stars using a subquery.

Practice Online


Movie database model

Query Visualization:

Duration:

Query visualization of Find the reviewer name, movie title, and number of stars for those movies which rating is the lowest one - Duration

Rows:

Query visualization of Find the reviewer name, movie title, and number of stars for those movies which rating is the lowest one - Rows

Cost:

Query visualization of Find the reviewer name, movie title, and number of stars for those movies which rating is the lowest one - Cost

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Previous: From the following tables, write a SQL query to find the movies, which have reviewed by any reviewer body except by 'Paul Monks'. Return movie title.
Next: From the following tables, write a SQL query to find the movies directed by ‘James Cameron’. Return movie title.

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