2026-LowQualityProblems.sql

-- 2026. Low-Quality Problems
-- Table: Problems
-- +-------------+------+
-- | Column Name | Type |
-- +-------------+------+
-- | problem_id  | int  |
-- | likes       | int  |
-- | dislikes    | int  |
-- +-------------+------+
-- In SQL, problem_id is the primary key column for this table.
-- Each row of this table indicates the number of likes and dislikes for a LeetCode problem.
-- Find the IDs of the low-quality problems. A LeetCode problem is low-quality if the like percentage of the problem (number of likes divided by the total number of votes) is strictly less than 60%.
-- Return the result table ordered by problem_id in ascending order.
-- The result format is in the following example.

-- Example 1:
-- Input: 
-- Problems table:
-- +------------+-------+----------+
-- | problem_id | likes | dislikes |
-- +------------+-------+----------+
-- | 6          | 1290  | 425      |
-- | 11         | 2677  | 8659     |
-- | 1          | 4446  | 2760     |
-- | 7          | 8569  | 6086     |
-- | 13         | 2050  | 4164     |
-- | 10         | 9002  | 7446     |
-- +------------+-------+----------+
-- Output: 
-- +------------+
-- | problem_id |
-- +------------+
-- | 7          |
-- | 10         |
-- | 11         |
-- | 13         |
-- +------------+
-- Explanation: The like percentages are as follows:
-- - Problem 1: (4446 / (4446 + 2760)) * 100 = 61.69858%
-- - Problem 6: (1290 / (1290 + 425)) * 100 = 75.21866%
-- - Problem 7: (8569 / (8569 + 6086)) * 100 = 58.47151%
-- - Problem 10: (9002 / (9002 + 7446)) * 100 = 54.73006%
-- - Problem 11: (2677 / (2677 + 8659)) * 100 = 23.61503%
-- - Problem 13: (2050 / (2050 + 4164)) * 100 = 32.99002%
-- Problems 7, 10, 11, and 13 are low-quality problems because their like percentages are less than 60%.

-- Create table If Not Exists Problems (problem_id int, likes int, dislikes int)
-- Truncate table Problems
-- insert into Problems (problem_id, likes, dislikes) values ('6', '1290', '425')
-- insert into Problems (problem_id, likes, dislikes) values ('11', '2677', '8659')
-- insert into Problems (problem_id, likes, dislikes) values ('1', '4446', '2760')
-- insert into Problems (problem_id, likes, dislikes) values ('7', '8569', '6086')
-- insert into Problems (problem_id, likes, dislikes) values ('13', '2050', '4164')
-- insert into Problems (problem_id, likes, dislikes) values ('10', '9002', '7446')

-- Write your MySQL query statement below
SELECT 
    problem_id 
FROM
    Problems 
WHERE
    -- 如果一个力扣问题的喜欢率（喜欢数除以总投票数）
    (likes / (likes  + dislikes) * 100) < 60 -- 喜欢率严格低于 60% ，则该问题为低质量问题
ORDER BY
    problem_id -- 按 problem_id 升序排列