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ptyadanaptyadana
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add many to many relationship
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‎Ultimate MySQL/13.Many To Many.sql

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/*Series Reviews*/
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CREATE TABLE reviewers(
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id INT AUTO_INCREMENT PRIMARY KEY,
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first_name VARCHAR(150),
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last_name VARCHAR(150)
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);
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CREATE TABLE series(
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id INT auto_increment PRIMARY KEY,
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title VARCHAR(200),
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released_year YEAR(4),
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genre VARCHAR(100)
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);
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CREATE TABLE reviews(
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id INT AUTO_INCREMENT PRIMARY KEY,
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rating DECIMAL (2,1),
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reviewer_id INT,
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series_id INT,
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FOREIGN KEY(reviewer_id) REFERENCES reviewers(id),
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FOREIGN KEY(series_id) REFERENCES series(id)
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);
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INSERT INTO series (title, released_year, genre) VALUES
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('Archer', 2009, 'Animation'),
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('Arrested Development', 2003, 'Comedy'),
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("Bob's Burgers", 2011, 'Animation'),
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('Bojack Horseman', 2014, 'Animation'),
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("Breaking Bad", 2008, 'Drama'),
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('Curb Your Enthusiasm', 2000, 'Comedy'),
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("Fargo", 2014, 'Drama'),
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('Freaks and Geeks', 1999, 'Comedy'),
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('General Hospital', 1963, 'Drama'),
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('Halt and Catch Fire', 2014, 'Drama'),
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('Malcolm In The Middle', 2000, 'Comedy'),
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('Pushing Daisies', 2007, 'Comedy'),
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('Seinfeld', 1989, 'Comedy'),
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('Stranger Things', 2016, 'Drama');
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INSERT INTO reviewers (first_name, last_name) VALUES
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('Thomas', 'Stoneman'),
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('Wyatt', 'Skaggs'),
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('Kimbra', 'Masters'),
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('Domingo', 'Cortes'),
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('Colt', 'Steele'),
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('Pinkie', 'Petit'),
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('Marlon', 'Crafford');
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INSERT INTO reviews(series_id, reviewer_id, rating) VALUES
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(1,1,8.0),(1,2,7.5),(1,3,8.5),(1,4,7.7),(1,5,8.9),
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(2,1,8.1),(2,4,6.0),(2,3,8.0),(2,6,8.4),(2,5,9.9),
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(3,1,7.0),(3,6,7.5),(3,4,8.0),(3,3,7.1),(3,5,8.0),
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(4,1,7.5),(4,3,7.8),(4,4,8.3),(4,2,7.6),(4,5,8.5),
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(5,1,9.5),(5,3,9.0),(5,4,9.1),(5,2,9.3),(5,5,9.9),
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(6,2,6.5),(6,3,7.8),(6,4,8.8),(6,2,8.4),(6,5,9.1),
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(7,2,9.1),(7,5,9.7),
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(8,4,8.5),(8,2,7.8),(8,6,8.8),(8,5,9.3),
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(9,2,5.5),(9,3,6.8),(9,4,5.8),(9,6,4.3),(9,5,4.5),
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(10,5,9.9),
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(13,3,8.0),(13,4,7.2),
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(14,2,8.5),(14,3,8.9),(14,4,8.9);
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/*------------------------------*/
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/*------------- Challenges --------------------*/
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/*+----------------------+--------+
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| title | rating |
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+----------------------+--------+
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| Archer | 8.0 |
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| Archer | 7.5 |
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| Archer | 8.5 |
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| Archer | 7.7 |
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| Archer | 8.9 |
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| Arrested Development | 8.1 |
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| Arrested Development | 6.0 |
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| Arrested Development | 8.0 |
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| Arrested Development | 8.4 |
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| Arrested Development | 9.9 |
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| Bob's Burgers | 7.0 |
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...
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+----------------------+--------+
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*/
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SELECT title,rating
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FROM series
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JOIN reviews ON series.id = reviews.series_id;
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/*+----------------------+------------+
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| title | avg_rating |
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+----------------------+------------+
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| General Hospital | 5.38000 |
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| Bob's Burgers | 7.52000 |
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| Seinfeld | 7.60000 |
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| Bojack Horseman | 7.94000 |
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| Arrested Development | 8.08000 |
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| Curb Your Enthusiasm | 8.12000 |
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| Archer | 8.12000 |
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| Freaks and Geeks | 8.60000 |
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| Stranger Things | 8.76667 |
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| Breaking Bad | 9.36000 |
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| Fargo | 9.40000 |
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| Halt and Catch Fire | 9.90000 |
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+----------------------+------------+
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*/
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/*+----------------------+------------+
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| title | avg_rating |
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+----------------------+------------+
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| General Hospital | 5.38000 |
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| Bob's Burgers | 7.52000 |
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| Seinfeld | 7.60000 |
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| Bojack Horseman | 7.94000 |
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| Arrested Development | 8.08000 |
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| Curb Your Enthusiasm | 8.12000 |
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| Archer | 8.12000 |
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| Freaks and Geeks | 8.60000 |
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| Stranger Things | 8.76667 |
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| Breaking Bad | 9.36000 |
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| Fargo | 9.40000 |
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| Halt and Catch Fire | 9.90000 |
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+----------------------+------------+
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*/
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SELECT title,AVG(rating) AS avg_rating
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FROM series
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JOIN reviews ON series.id = reviews.series_id
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GROUP BY series.id
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ORDER BY avg_rating;
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/*
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+------------+-----------+--------+
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| first_name | last_name | rating |
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+------------+-----------+--------+
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| Thomas | Stoneman | 8.0 |
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| Thomas | Stoneman | 8.1 |
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| Thomas | Stoneman | 7.0 |
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| Thomas | Stoneman | 7.5 |
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| Thomas | Stoneman | 9.5 |
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| Wyatt | Skaggs | 7.5 |
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| Wyatt | Skaggs | 7.6 |
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| Wyatt | Skaggs | 9.3 |
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| Wyatt | Skaggs | 6.5 |
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| Wyatt | Skaggs | 8.4 |
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| Wyatt | Skaggs | 9.1 |
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| Wyatt | Skaggs | 7.8 |
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| Wyatt | Skaggs | 5.5 |
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| Wyatt | Skaggs | 8.5 |
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| Kimbra | Masters | 8.5 |
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| Kimbra | Masters | 8.0 |
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| Kimbra | Masters | 7.1 |
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| Kimbra | Masters | 7.8 |
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| Kimbra | Masters | 9.0 |
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| Kimbra | Masters | 7.8 |
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+------------+-----------+--------+
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*/
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SELECT first_name,last_name
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FROM reviewers
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JOIN reviews ON reviewers.id = reviews.reviewer_id;
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/*+-----------------------+
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| unreviewed_series |
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+-----------------------+
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| Malcolm In The Middle |
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| Pushing Daisies |
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+-----------------------+*/
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SELECT title AS unreviewed_series
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FROM series
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LEFT JOIN reviews ON series.id = reviews.series_id
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WHERE reviews.id IS NULL;
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/*+-----------+------------+
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| genre | avg_rating |
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+-----------+------------+
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| Animation | 7.86000 |
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| Comedy | 8.16250 |
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| Drama | 8.04375 |
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+-----------+------------+*/
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SELECT genre, ROUND(AVG(rating),2) AS avg_rating
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FROM series
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JOIN reviews ON series.id = reviews.series_id
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GROUP BY genre;
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/*+------------+-----------+-------+-----+-----+---------+----------+
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| first_name | last_name | COUNT | MIN | MAX | AVG | STATUS |
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+------------+-----------+-------+-----+-----+---------+----------+
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| Thomas | Stoneman | 5 | 7.0 | 9.5 | 8.02000 | ACTIVE |
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| Wyatt | Skaggs | 9 | 5.5 | 9.3 | 7.80000 | ACTIVE |
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| Kimbra | Masters | 9 | 6.8 | 9.0 | 7.98889 | ACTIVE |
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| Domingo | Cortes | 10 | 5.8 | 9.1 | 7.83000 | ACTIVE |
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| Colt | Steele | 10 | 4.5 | 9.9 | 8.77000 | ACTIVE |
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| Pinkie | Petit | 4 | 4.3 | 8.8 | 7.25000 | ACTIVE |
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| Marlon | Crafford | 0 | 0.0 | 0.0 | 0.00000 | INACTIVE |
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+------------+-----------+-------+-----+-----+---------+----------+*/
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SELECT first_name,last_name,
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COUNT(rating) AS 'COUNT',
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IFNULL(MIN(rating),0) AS 'MIN',
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IFNULL(MAX(rating),0) AS 'MAX',
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IFNULL(ROUND(AVG(rating),2),0) AS 'AVG',
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CASE
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WHEN COUNT(rating) > 10 THEN 'POWER USER'
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WHEN COUNT(rating) > 0 THEN 'ACTIVE'
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ELSE 'INACTIVE'
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END AS 'STATUS'
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FROM reviewers
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LEFT JOIN reviews ON reviewers.id = reviews.reviewer_id
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GROUP BY reviewers.id;
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/*+----------------------+--------+-----------------+
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| title | rating | reviewer |
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+----------------------+--------+-----------------+
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| Archer | 8.0 | Thomas Stoneman |
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| Archer | 7.7 | Domingo Cortes |
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| Archer | 8.5 | Kimbra Masters |
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| Archer | 7.5 | Wyatt Skaggs |
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| Archer | 8.9 | Colt Steele |
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| Arrested Development | 8.4 | Pinkie Petit |
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| Arrested Development | 9.9 | Colt Steele |
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| Arrested Development | 8.1 | Thomas Stoneman |
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| Arrested Development | 6.0 | Domingo Cortes |
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| Arrested Development | 8.0 | Kimbra Masters |
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| Bob's Burgers | 7.0 | Thomas Stoneman |
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| Bob's Burgers | 8.0 | Domingo Cortes |
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| Bob's Burgers | 7.1 | Kimbra Masters |
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| Bob's Burgers | 7.5 | Pinkie Petit |
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| Bob's Burgers | 8.0 | Colt Steele |
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+----------------------+--------+-----------------+*/
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SELECT title,rating,CONCAT(first_name,' ',last_name) AS 'reviewer'
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FROM series
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JOIN reviews ON series.id = reviews.series_id
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JOIN reviewers ON reviewers.id = reviews.reviewer_id
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ORDER BY title, rating DESC;

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