SQL 50 - LeetCode

Solutions for SQL 50 Study Plan on LeetCode

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1757 - Recyclable and Low Fat Products

SELECT product_id
FROM Products
WHERE low_fats = 'Y'
AND recyclable = 'Y'

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584 - Find Customer Referee

SELECT name 
FROM Customer 
WHERE referee_id != 2 OR referee_id IS null

595 - Big Countries

SELECT name, population, area
FROM WORLD
WHERE area >= 3000000
OR population >= 25000000

1148 - Article Views I

SELECT DISTINCT author_id as id
FROM Views
WHERE viewer_id >= 1
AND author_id = viewer_id
ORDER BY author_id

1683 - Invalid Tweets

SELECT tweet_id
FROM Tweets
WHERE length(content) > 15

1378 - Replace Employee ID With The Unique Identifier

SELECT unique_id, name
FROM Employees e
LEFT JOIN EmployeeUNI eu
ON e.id = eu.id

1068 - Product Sales Analysis I

SELECT product_name, year, price
FROM Sales s
LEFT JOIN Product p
ON s.product_id = p.product_id

1581 - Customer Who Visited but Did Not Make Any Transactions

SELECT customer_id, COUNT(*) as count_no_trans
FROM Visits 
WHERE visit_id NOT IN (SELECT DISTINCT visit_id FROM Transactions)
GROUP BY customer_id