SQL exercises on movie Database: Find the names of all reviewers who have ratings with a NULL value
SQL movie Database: Subquery Exercise-8 with Solution
8. From the following table, write a SQL query to find those reviewers who have not given a rating to certain films. Return reviewer name.
Sample table: reviewer
Sample table: rating
Sample Solution:
SELECT DISTINCT rev_name
FROM reviewer
WHERE rev_id IN (
SELECT rev_id
FROM rating
WHERE rev_stars IS NULL);
Sample Output:
rev_name -------------------------------- Neal Wruck Scott LeBrun (2 rows)
Code Explanation:
The said query in SQL which selects distinct reviewer names from the 'reviewer' table where the corresponding reviewer IDs have at least one review with a null rating in the 'Rating' table. The results are ordered by reviewer name in ascending order.
The query uses a subquery to find the reviewer IDs with null ratings, and then selects the distinct reviewer names corresponding to those IDs. The "DISTINCT" keyword ensures that only unique reviewer names are returned.
Practice Online

Query Visualization:
Duration:

Rows:

Cost:

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Previous: From the following table, write a SQL query to find those movies, which have no ratings. Return movie title.
Next: From the following tables, write a SQL query to find those movies, which reviewed by a reviewer and got a rating. Sort the result-set in ascending order by reviewer name, movie title, review Stars. Return reviewer name, movie title, review Stars.
What is the difficulty level of this exercise?
Test your Programming skills with w3resource's quiz.
SQL: Tips of the Day
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SELECT * FROM ( SELECT ROW_NUMBER() OVER ( ORDER BY OrderDate ) AS RowNum, * FROM Orders WHERE OrderDate >= '1980-01-01' ) AS RowConstrainedResult WHERE RowNum >= 1 AND RowNum < 20 ORDER BY RowNum
Database: SQL Server
Ref: https://bit.ly/3MGrNlk
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