方法二:连接查询筛选出有效订单记录集合 https://leetcode-cn.com/problems/trips-and-users/solution/san-chong-jie-fa-cong-nan-dao-yi-zong-you-gua-he-n/ 计算订单取消率还可以用avg(Status!='completed'): https://leetcode-cn.com/problems/trips-and-users/solution/ci-ti-bu-nan-wei-fu-za-er-...
6. LEETCODE（⭐⭐⭐）https://leetcode-cn.com/problemset/database/ LEETCODE上面有很多算法类...
1 SELECT question_id AS survey_log 2 FROM 3 (SELECT 4 question_id, 5 SUM(IF(action='answer',1,0)) as answer_num, 6 SUM(IF(action='show',1,0))as show_num 7 -- SUM(case when action="answer" THEN 1 ELSE 0 END) AS num_answer, 8 -- SUM(case when action="show" THEN 1 ...
613.Shortest Distance in a Line (easy) 思路:table内交生成所有可能的点对(应避免重复以提高效率), 然后计算最小距离。 selectmin(ABS(p1.x-p2.x))asshortestfrompointp1joinpointp2onp1.x<p2.x 578.Get Highest Answer Rate Question (medium) 思路: 对于每一个question_id分组,计算出它的Answer rate。
Explanation:The CASE statement is used to categorize employees based on their salary. The result categorizes them as “High”, “Medium”, or “Low”. 9. Find Duplicate Records Question: Write a query to find duplicate email addresses from the users table. Assume the users table has a colum...
select a.device_id, university, ifnull(count(question_id),0) as question_cnt, count(if(result='right',1,null)) as right_question_cnt from user_profile a left join question_practice_detail b on a.device_id=b.device_id where university='复旦大学' and (month(date)='08' or date is ...
SQLZoo QuestionAnswer Richer Than UK Solution Bigger Than Every Country In Europe Solution Neighbours of Argentina and Australia Solution Teams that have coach Fernando Santos Solution Busy years for John Travolta SolutionAbout Solutions to Problems For SQL on Leetcode, Hackerrank & DataLemur Topics ...
7.578. Get Highest Answer Rate Question 善用order by 将query写的简洁一些 注意null是不计算在count以内的 善用if 函数 if(条件,条件为真值,条件不为真值) 简洁版:SELECT question_id AS 'survey_log' FROM survey_log GROUP BY question_id ORDER BY COUNT(answer_id) / COUNT(IF(action = 'show', 1...
题目选自leetcode 上的题库可能不一定都是最优解,答案仅供参考 每道题后面都应相应的难度等级,如果没时间做的话 可以在leetcode 按出题频率刷题 祝大家面试取得好的成绩512. 游戏玩法分析 II难度简单SQL架构Table: Activity+---+---+ | Column Name | Type | +---+---+ | player_id | int | | dev...
Here’s also the code output. 2. Count Student Number in Departments The question from LeetCode asks you the following. “Write an SQL query to report the respective department name and number of students majoring in each department for all departments in theDepartmenttable (even ones with no...