Last updated on April 15, 2020, covered 104 LeetCode SQL questions
After finishing all 102 LeetCode SQL questions, I feel the urge to summarize them by topics they are trying to test.
This note aims to help people learn and review SQL effeciently, espeically when trying to have a quick catch up on a certain topic, e.g. complex join, window function, recursive CTE and etc.
And for the first draft, I mainly focus on T-SQL/MS SQL Server.
# | Title | Difficulty | Solution |
---|---|---|---|
182 | Duplicate Emails | Easy | Soln. |
511 | Game Play Analysis I | Easy | Soln. |
578 | Get Highest Answer Rate Question | Medium | Soln. |
584 | Find Customer Referee | Easy | Soln. |
586 | Customer Placing the Largest Number of Orders | Easy | Soln. |
595 | Big Countries | Easy | Soln. |
596 | Classes More Than 5 Students | Easy | Soln. |
619 | Biggest Single Number | Easy | Soln. |
620 | Not Boring Movies | Easy | Soln. |
1050 | Actors and Directors Who Cooperated At Least Three Times | Easy | Soln. |
1069 | Product Sales Analysis II | Easy | Soln. |
1076 | Project Employees II | Easy | Soln. |
1082 | Sales Analysis I | Easy | Soln. |
1141 | User Activity for the Past 30 Days I | Easy | Soln. |
1148 | Article Views I | Easy | Soln. |
1149 | Article Views II | Medium | Soln. |
# | Title | Difficulty | Solution |
---|---|---|---|
196 | Delete Duplicate Emails | Easy | Soln. |
627 | Swap Salary | Easy | Soln. |
- Simple Join
- Advanced Join
# | Title | Difficulty | Solution |
---|---|---|---|
180 | Consecutive Numbers | Medium | Soln. |
196 | Delete Duplicate Emails | Easy | Soln. |
534 | Game Play Analysis III | Medium | Soln. |
569 | Median Employee Salary | Hard | Soln. |
579 | Find Cumulative Salary of an Employee | Hard | Soln. |
601 | Human Traffic of Stadium | Hard | Soln. |
603 | Consecutive Available Seats | Easy | Soln. |
612 | Shortest Distance in a Plane | Medium | Soln. |
613 | Shortest Distance in a Line | Easy | Soln. |
1097 | Game Play Analysis V | Hard | Soln. |
1126 | Active Businesses | Medium | Soln. |
1127 | User Purchase Platform | Hard | Soln. |
1159 | Market Analysis II | Medium | Soln. |
1194 | Tournament Winners | Hard | Soln. |
1212 | Team Scores in Football Tournament | Medium | Soln. |
1225 | Report Contiguous Dates | Hard | Soln. |
1251 | Average Selling Price | Easy | Soln. |
1285 | Find the Start and End Number of Continuous Ranges | Medium | Soln. |
1308 | Running Total for Different Genders | Medium | Soln. |
1321 | Restaurant Growth | Medium | Soln. |
1369 | Get the Second Most Recent Activity | Hard | Soln. |
- Simple Subquery
- Advanced Subquery
# | Title | Difficulty | Solution |
---|---|---|---|
262 | Trips and Users | Hard | Soln. |
550 | Game Play Analysis IV | Medium | Soln. |
569 | Median Employee Salary | Hard | Soln. |
585 | Investments in 2016 | Medium | Soln. |
597 | Friend Requests I: Overall Acceptance Rate | Easy | Soln. |
601 | Human Traffic of Stadium | Hard | Soln. |
1077 | Project Employees II | Medium | Soln. |
1127 | User Purchase Platform | Hard | Soln. |
1159 | Market Analysis II | Medium | Soln. |
1164 | Product Price at a Given Date | Medium | Soln. |
1194 | Tournament Winners | Hard | Soln. |
1205 | Monthly Transactions II | Medium | Soln. |
1270 | All People Report to the Given Manager | Medium | Soln. |
1398 | Customers Who Bought Products A and B but Not C | Medium | Soln. |
- Recursive CTE
# | Title | Difficulty | Solution |
---|---|---|---|
1270 | All People Report to the Given Manager | Medium | Soln. |
1336 | Number of Transactions per Visit | Hard | Soln. |
1384 | Total Sales Amount by Year | Hard | Soln. |
# | Title | Difficulty | Solution |
---|---|---|---|
262 | Trips and Users | Hard | Soln. |
597 | Friend Requests I: Overall Acceptance Rate | Easy | Soln. |
608 | Tree Node | Medium | Soln. |
610 | Triangle Judgement | Easy | Soln. |
615 | Average Salary: Departments VS Company | Hard | Soln. |
618 | Students Report By Geography | Hard | Soln. |
626 | Exchange Seats | Medium | Soln. |
627 | Swap Salary | Easy | Soln. |
1126 | Active Businesses | Medium | Soln. |
1142 | User Activity for the Past 30 Days II | Easy | Soln. |
1158 | Market Analysis I | Medium | Soln. |
1159 | Market Analysis II | Medium | Soln. |
1173 | Immediate Food Delivery I | Easy | Soln. |
1174 | Immediate Food Delivery II | Medium | Soln. |
1193 | Monthly Transactions I | Medium | Soln. |
1194 | Tournament Winners | Hard | Soln. |
1211 | Queries Quality and Percentage | Easy | Soln. |
1212 | Team Scores in Football Tournament | Medium | Soln. |
1264 | Page Recommendations | Medium | Soln. |
1294 | Weather Type in Each Country | Easy | Soln. |
1322 | Ads Performance | Easy | Soln. |
1393 | Capital Gain/Loss | Medium | Soln. |
1398 | Customers Who Bought Products A and B but Not C | Medium | Soln. |
# | Title | Difficulty | Solution |
---|---|---|---|
176 | Second Highest Salary | Easy | Soln. |
177 | Nth Highest Salary | Medium | Soln. |
1321 | Restaurant Growth | Medium | Soln. |
# | Title | Difficulty | Solution |
---|---|---|---|
602 | Friend Requests II: Who Has the Most Friends | Medium | Soln. |
618 | Students Report By Geography | Hard | Soln. |
1179 | Reformat Department Table | Easy | Soln. |
1322 | Ads Performance | Easy | Soln. |
# | Title | Difficulty | Solution |
---|---|---|---|
597 | Friend Requests I: Overall Acceptance Rate | Easy | Soln. |
1098 | Unpopular Books | Medium | Soln. |
1107 | New Users Daily Count | Medium | Soln. |
1113 | Reported Posts | Easy | Soln. |