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DATABASE_README_EN.md

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Database Practice

δΈ­ζ–‡ζ–‡ζ‘£

Solutions

Press Control + F(or Command + F on the Mac) to search anything you want.

# Solution Tags Difficulty Remark
0175 Combine Two Tables Database Easy
0176 Second Highest Salary Database Medium
0177 Nth Highest Salary Database Medium
0178 Rank Scores Database Medium
0180 Consecutive Numbers Database Medium
0181 Employees Earning More Than Their Managers Database Easy
0182 Duplicate Emails Database Easy
0183 Customers Who Never Order Database Easy
0184 Department Highest Salary Database Medium
0185 Department Top Three Salaries Database Hard
0196 Delete Duplicate Emails Database Easy
0197 Rising Temperature Database Easy
0262 Trips and Users Database Hard
0511 Game Play Analysis I Database Easy
0512 Game Play Analysis II Database Easy πŸ”’
0534 Game Play Analysis III Database Medium πŸ”’
0550 Game Play Analysis IV Database Medium
0569 Median Employee Salary Database Hard πŸ”’
0570 Managers with at Least 5 Direct Reports Database Medium
0571 Find Median Given Frequency of Numbers Database Hard πŸ”’
0574 Winning Candidate Database Medium πŸ”’
0577 Employee Bonus Database Easy
0578 Get Highest Answer Rate Question Database Medium πŸ”’
0579 Find Cumulative Salary of an Employee Database Hard πŸ”’
0580 Count Student Number in Departments Database Medium πŸ”’
0584 Find Customer Referee Database Easy
0585 Investments in 2016 Database Medium
0586 Customer Placing the Largest Number of Orders Database Easy
0595 Big Countries Database Easy
0596 Classes More Than 5 Students Database Easy
0597 Friend Requests I Overall Acceptance Rate Database Easy πŸ”’
0601 Human Traffic of Stadium Database Hard
0602 Friend Requests II Who Has the Most Friends Database Medium
0603 Consecutive Available Seats Database Easy πŸ”’
0607 Sales Person Database Easy
0608 Tree Node Database Medium
0610 Triangle Judgement Database Easy
0612 Shortest Distance in a Plane Database Medium πŸ”’
0613 Shortest Distance in a Line Database Easy πŸ”’
0614 Second Degree Follower Database Medium πŸ”’
0615 Average Salary Departments VS Company Database Hard πŸ”’
0618 Students Report By Geography Database Hard πŸ”’
0619 Biggest Single Number Database Easy
0620 Not Boring Movies Database Easy
0626 Exchange Seats Database Medium
0627 Swap Salary Database Easy
1045 Customers Who Bought All Products Database Medium
1050 Actors and Directors Who Cooperated At Least Three Times Database Easy
1068 Product Sales Analysis I Database Easy
1069 Product Sales Analysis II Database Easy πŸ”’
1070 Product Sales Analysis III Database Medium
1075 Project Employees I Database Easy
1076 Project Employees II Database Easy πŸ”’
1077 Project Employees III Database Medium πŸ”’
1082 Sales Analysis I Database Easy πŸ”’
1083 Sales Analysis II Database Easy πŸ”’
1084 Sales Analysis III Database Easy
1097 Game Play Analysis V Database Hard πŸ”’
1098 Unpopular Books Database Medium πŸ”’
1107 New Users Daily Count Database Medium πŸ”’
1112 Highest Grade For Each Student Database Medium πŸ”’
1113 Reported Posts Database Easy πŸ”’
1126 Active Businesses Database Medium πŸ”’
1127 User Purchase Platform Database Hard πŸ”’
1132 Reported Posts II Database Medium πŸ”’
1141 User Activity for the Past 30 Days I Database Easy
1142 User Activity for the Past 30 Days II Database Easy πŸ”’
1148 Article Views I Database Easy
1149 Article Views II Database Medium πŸ”’
1158 Market Analysis I Database Medium
1159 Market Analysis II Database Hard πŸ”’
1164 Product Price at a Given Date Database Medium
1173 Immediate Food Delivery I Database Easy πŸ”’
1174 Immediate Food Delivery II Database Medium
1179 Reformat Department Table Database Easy
1193 Monthly Transactions I Database Medium
1194 Tournament Winners Database Hard πŸ”’
1204 Last Person to Fit in the Bus Database Medium
1205 Monthly Transactions II Database Medium πŸ”’
1211 Queries Quality and Percentage Database Easy
1212 Team Scores in Football Tournament Database Medium πŸ”’
1225 Report Contiguous Dates Database Hard πŸ”’
1241 Number of Comments per Post Database Easy πŸ”’
1251 Average Selling Price Database Easy
1264 Page Recommendations Database Medium πŸ”’
1270 All People Report to the Given Manager Database Medium πŸ”’
1280 Students and Examinations Database Easy
1285 Find the Start and End Number of Continuous Ranges Database Medium πŸ”’
1294 Weather Type in Each Country Database Easy πŸ”’
1303 Find the Team Size Database Easy πŸ”’
1308 Running Total for Different Genders Database Medium πŸ”’
1321 Restaurant Growth Database Medium
1322 Ads Performance Database Easy πŸ”’
1327 List the Products Ordered in a Period Database Easy
1336 Number of Transactions per Visit Database Hard πŸ”’
1341 Movie Rating Database Medium
1350 Students With Invalid Departments Database Easy πŸ”’
1355 Activity Participants Database Medium πŸ”’
1364 Number of Trusted Contacts of a Customer Database Medium πŸ”’
1369 Get the Second Most Recent Activity Database Hard πŸ”’
1378 Replace Employee ID With The Unique Identifier Database Easy
1384 Total Sales Amount by Year Database Hard πŸ”’
1393 Capital GainLoss Database Medium
1398 Customers Who Bought Products A and B but Not C Database Medium πŸ”’
1407 Top Travellers Database Easy
1412 Find the Quiet Students in All Exams Database Hard πŸ”’
1421 NPV Queries Database Easy πŸ”’
1435 Create a Session Bar Chart Database Easy πŸ”’
1440 Evaluate Boolean Expression Database Medium πŸ”’
1445 Apples & Oranges Database Medium πŸ”’
1454 Active Users Database Medium πŸ”’
1459 Rectangles Area Database Medium πŸ”’
1468 Calculate Salaries Database Medium πŸ”’
1479 Sales by Day of the Week Database Hard πŸ”’
1484 Group Sold Products By The Date Database Easy
1495 Friendly Movies Streamed Last Month Database Easy πŸ”’
1501 Countries You Can Safely Invest In Database Medium πŸ”’
1511 Customer Order Frequency Database Easy πŸ”’
1517 Find Users With Valid E-Mails Database Easy
1527 Patients With a Condition Database Easy
1532 The Most Recent Three Orders Database Medium πŸ”’
1543 Fix Product Name Format Database Easy πŸ”’
1549 The Most Recent Orders for Each Product Database Medium πŸ”’
1555 Bank Account Summary Database Medium πŸ”’
1565 Unique Orders and Customers Per Month Database Easy πŸ”’
1571 Warehouse Manager Database Easy πŸ”’
1581 Customer Who Visited but Did Not Make Any Transactions Database Easy
1587 Bank Account Summary II Database Easy
1596 The Most Frequently Ordered Products for Each Customer Database Medium πŸ”’
1607 Sellers With No Sales Database Easy πŸ”’
1613 Find the Missing IDs Database Medium πŸ”’
1623 All Valid Triplets That Can Represent a Country Database Easy πŸ”’
1633 Percentage of Users Attended a Contest Database Easy
1635 Hopper Company Queries I Database Hard πŸ”’
1645 Hopper Company Queries II Database Hard πŸ”’
1651 Hopper Company Queries III Database Hard πŸ”’
1661 Average Time of Process per Machine Database Easy
1667 Fix Names in a Table Database Easy
1677 Product's Worth Over Invoices Database Easy πŸ”’
1683 Invalid Tweets Database Easy
1693 Daily Leads and Partners Database Easy
1699 Number of Calls Between Two Persons Database Medium πŸ”’
1709 Biggest Window Between Visits Database Medium πŸ”’
1715 Count Apples and Oranges Database Medium πŸ”’
1729 Find Followers Count Database Easy
1731 The Number of Employees Which Report to Each Employee Database Easy
1741 Find Total Time Spent by Each Employee Database Easy
1747 Leetflex Banned Accounts Database Medium πŸ”’
1757 Recyclable and Low Fat Products Database Easy
1767 Find the Subtasks That Did Not Execute Database Hard πŸ”’
1777 Product's Price for Each Store Database Easy πŸ”’
1783 Grand Slam Titles Database Medium πŸ”’
1789 Primary Department for Each Employee Database Easy
1795 Rearrange Products Table Database Easy
1809 Ad-Free Sessions Database Easy πŸ”’
1811 Find Interview Candidates Database Medium πŸ”’
1821 Find Customers With Positive Revenue this Year Database Easy πŸ”’
1831 Maximum Transaction Each Day Database Medium πŸ”’
1841 League Statistics Database Medium πŸ”’
1843 Suspicious Bank Accounts Database Medium πŸ”’
1853 Convert Date Format Database Easy πŸ”’
1867 Orders With Maximum Quantity Above Average Database Medium πŸ”’
1873 Calculate Special Bonus Database Easy
1875 Group Employees of the Same Salary Database Medium πŸ”’
1890 The Latest Login in 2020 Database Easy
1892 Page Recommendations II Database Hard πŸ”’
1907 Count Salary Categories Database Medium
1917 Leetcodify Friends Recommendations Database Hard πŸ”’
1919 Leetcodify Similar Friends Database Hard πŸ”’
1934 Confirmation Rate Database Medium
1939 Users That Actively Request Confirmation Messages Database Easy πŸ”’
1949 Strong Friendship Database Medium πŸ”’
1951 All the Pairs With the Maximum Number of Common Followers Database Medium πŸ”’
1965 Employees With Missing Information Database Easy
1972 First and Last Call On the Same Day Database Hard πŸ”’
1978 Employees Whose Manager Left the Company Database Easy
1988 Find Cutoff Score for Each School Database Medium πŸ”’
1990 Count the Number of Experiments Database Medium πŸ”’
2004 The Number of Seniors and Juniors to Join the Company Database Hard πŸ”’
2010 The Number of Seniors and Juniors to Join the Company II Database Hard πŸ”’
2020 Number of Accounts That Did Not Stream Database Medium πŸ”’
2026 Low-Quality Problems Database Easy πŸ”’
2041 Accepted Candidates From the Interviews Database Medium πŸ”’
2051 The Category of Each Member in the Store Database Medium πŸ”’
2066 Account Balance Database Medium πŸ”’
2072 The Winner University Database Easy πŸ”’
2082 The Number of Rich Customers Database Easy πŸ”’
2084 Drop Type 1 Orders for Customers With Type 0 Orders Database Medium πŸ”’
2112 The Airport With the Most Traffic Database Medium πŸ”’
2118 Build the Equation Database Hard πŸ”’
2142 The Number of Passengers in Each Bus I Database Medium πŸ”’
2153 The Number of Passengers in Each Bus II Database Hard πŸ”’
2159 Order Two Columns Independently Database Medium πŸ”’
2173 Longest Winning Streak Database Hard πŸ”’
2175 The Change in Global Rankings Database Medium πŸ”’
2199 Finding the Topic of Each Post Database Hard πŸ”’
2205 The Number of Users That Are Eligible for Discount Database Easy πŸ”’
2228 Users With Two Purchases Within Seven Days Database Medium πŸ”’
2230 The Users That Are Eligible for Discount Database Easy πŸ”’
2238 Number of Times a Driver Was a Passenger Database Medium πŸ”’
2252 Dynamic Pivoting of a Table Database Hard πŸ”’
2253 Dynamic Unpivoting of a Table Database Hard πŸ”’
2292 Products With Three or More Orders in Two Consecutive Years Database Medium πŸ”’
2298 Tasks Count in the Weekend Database Medium πŸ”’
2308 Arrange Table by Gender Database Medium πŸ”’
2314 The First Day of the Maximum Recorded Degree in Each City Database Medium πŸ”’
2324 Product Sales Analysis IV Database Medium πŸ”’
2329 Product Sales Analysis V Database Easy πŸ”’
2339 All the Matches of the League Database Easy πŸ”’
2346 Compute the Rank as a Percentage Database Medium πŸ”’
2356 Number of Unique Subjects Taught by Each Teacher Database Easy
2362 Generate the Invoice Database Hard πŸ”’
2372 Calculate the Influence of Each Salesperson Database Medium πŸ”’
2377 Sort the Olympic Table Database Easy πŸ”’
2388 Change Null Values in a Table to the Previous Value Database Medium πŸ”’
2394 Employees With Deductions Database Medium πŸ”’
2474 Customers With Strictly Increasing Purchases Database Hard πŸ”’
2480 Form a Chemical Bond Database Easy πŸ”’
2494 Merge Overlapping Events in the Same Hall Database Hard πŸ”’
2504 Concatenate the Name and the Profession Database Easy πŸ”’
2668 Find Latest Salaries Database Easy πŸ”’
2669 Count Artist Occurrences On Spotify Ranking List Database Easy πŸ”’
2686 Immediate Food Delivery III Database Medium πŸ”’
2687 Bikes Last Time Used Database Easy πŸ”’
2688 Find Active Users Database Medium πŸ”’
2701 Consecutive Transactions with Increasing Amounts Database Hard πŸ”’
2720 Popularity Percentage Database Hard πŸ”’
2738 Count Occurrences in Text Database Medium πŸ”’
2752 Customers with Maximum Number of Transactions on Consecutive Days Database Hard πŸ”’
2783 Flight Occupancy and Waitlist Analysis Database Medium πŸ”’
2793 Status of Flight Tickets Hard πŸ”’
2820 Election Results Medium πŸ”’
2837 Total Traveled Distance Database Easy πŸ”’
2853 Highest Salaries Difference Database Easy πŸ”’
2854 Rolling Average Steps Database Medium πŸ”’
2893 Calculate Orders Within Each Interval Database Medium πŸ”’
2922 Market Analysis III Database Medium πŸ”’
2978 Symmetric Coordinates Database Medium πŸ”’
2984 Find Peak Calling Hours for Each City Database Medium πŸ”’
2985 Calculate Compressed Mean Database Easy πŸ”’
2986 Find Third Transaction Database Medium πŸ”’
2987 Find Expensive Cities Database Easy πŸ”’
2988 Manager of the Largest Department Database Medium πŸ”’
2989 Class Performance Database Medium πŸ”’
2990 Loan Types Database Easy πŸ”’
2991 Top Three Wineries Database Hard πŸ”’
2993 Friday Purchases I Database Medium πŸ”’
2994 Friday Purchases II Database Hard πŸ”’
2995 Viewers Turned Streamers Database Hard πŸ”’
3050 Pizza Toppings Cost Analysis Database Medium πŸ”’
3051 Find Candidates for Data Scientist Position Database Easy πŸ”’
3052 Maximize Items Database Hard πŸ”’
3053 Classifying Triangles by Lengths Database Easy πŸ”’
3054 Binary Tree Nodes Database Medium πŸ”’
3055 Top Percentile Fraud Database Medium πŸ”’
3056 Snaps Analysis Database Medium πŸ”’
3057 Employees Project Allocation Database Hard πŸ”’
3058 Friends With No Mutual Friends Database Medium πŸ”’
3059 Find All Unique Email Domains Database Easy πŸ”’
3060 User Activities within Time Bounds Database Hard πŸ”’
3061 Calculate Trapping Rain Water Database Hard πŸ”’

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