# Database Practice [δΈζζζ‘£](/solution/DATABASE_README.md) ## Solutions Press <kbd>Control</kbd> + <kbd>F</kbd>(or <kbd>Command</kbd> + <kbd>F</kbd> on the Mac) to search anything you want. | # | Solution | Tags | Difficulty | Remark | | ---- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------- | ---------- | ------ | | 0175 | [Combine Two Tables](/solution/0100-0199/0175.Combine%20Two%20Tables/README_EN.md) | `Database` | Easy | | | 0176 | [Second Highest Salary](/solution/0100-0199/0176.Second%20Highest%20Salary/README_EN.md) | `Database` | Medium | | | 0177 | [Nth Highest Salary](/solution/0100-0199/0177.Nth%20Highest%20Salary/README_EN.md) | `Database` | Medium | | | 0178 | [Rank Scores](/solution/0100-0199/0178.Rank%20Scores/README_EN.md) | `Database` | Medium | | | 0180 | [Consecutive Numbers](/solution/0100-0199/0180.Consecutive%20Numbers/README_EN.md) | `Database` | Medium | | | 0181 | [Employees Earning More Than Their Managers](/solution/0100-0199/0181.Employees%20Earning%20More%20Than%20Their%20Managers/README_EN.md) | `Database` | Easy | | | 0182 | [Duplicate Emails](/solution/0100-0199/0182.Duplicate%20Emails/README_EN.md) | `Database` | Easy | | | 0183 | [Customers Who Never Order](/solution/0100-0199/0183.Customers%20Who%20Never%20Order/README_EN.md) | `Database` | Easy | | | 0184 | [Department Highest Salary](/solution/0100-0199/0184.Department%20Highest%20Salary/README_EN.md) | `Database` | Medium | | | 0185 | [Department Top Three Salaries](/solution/0100-0199/0185.Department%20Top%20Three%20Salaries/README_EN.md) | `Database` | Hard | | | 0196 | [Delete Duplicate Emails](/solution/0100-0199/0196.Delete%20Duplicate%20Emails/README_EN.md) | `Database` | Easy | | | 0197 | [Rising Temperature](/solution/0100-0199/0197.Rising%20Temperature/README_EN.md) | `Database` | Easy | | | 0262 | [Trips and Users](/solution/0200-0299/0262.Trips%20and%20Users/README_EN.md) | `Database` | Hard | | | 0511 | [Game Play Analysis I](/solution/0500-0599/0511.Game%20Play%20Analysis%20I/README_EN.md) | `Database` | Easy | | | 0512 | [Game Play Analysis II](/solution/0500-0599/0512.Game%20Play%20Analysis%20II/README_EN.md) | `Database` | Easy | π | | 0534 | [Game Play Analysis III](/solution/0500-0599/0534.Game%20Play%20Analysis%20III/README_EN.md) | `Database` | Medium | π | | 0550 | [Game Play Analysis IV](/solution/0500-0599/0550.Game%20Play%20Analysis%20IV/README_EN.md) | `Database` | Medium | | | 0569 | [Median Employee Salary](/solution/0500-0599/0569.Median%20Employee%20Salary/README_EN.md) | `Database` | Hard | π | | 0570 | [Managers with at Least 5 Direct Reports](/solution/0500-0599/0570.Managers%20with%20at%20Least%205%20Direct%20Reports/README_EN.md) | `Database` | Medium | | | 0571 | [Find Median Given Frequency of Numbers](/solution/0500-0599/0571.Find%20Median%20Given%20Frequency%20of%20Numbers/README_EN.md) | `Database` | Hard | π | | 0574 | [Winning Candidate](/solution/0500-0599/0574.Winning%20Candidate/README_EN.md) | `Database` | Medium | π | | 0577 | [Employee Bonus](/solution/0500-0599/0577.Employee%20Bonus/README_EN.md) | `Database` | Easy | | | 0578 | [Get Highest Answer Rate Question](/solution/0500-0599/0578.Get%20Highest%20Answer%20Rate%20Question/README_EN.md) | `Database` | Medium | π | | 0579 | [Find Cumulative Salary of an Employee](/solution/0500-0599/0579.Find%20Cumulative%20Salary%20of%20an%20Employee/README_EN.md) | `Database` | Hard | π | | 0580 | [Count Student Number in Departments](/solution/0500-0599/0580.Count%20Student%20Number%20in%20Departments/README_EN.md) | `Database` | Medium | π | | 0584 | [Find Customer Referee](/solution/0500-0599/0584.Find%20Customer%20Referee/README_EN.md) | `Database` | Easy | | | 0585 | [Investments in 2016](/solution/0500-0599/0585.Investments%20in%202016/README_EN.md) | `Database` | Medium | | | 0586 | [Customer Placing the Largest Number of Orders](/solution/0500-0599/0586.Customer%20Placing%20the%20Largest%20Number%20of%20Orders/README_EN.md) | `Database` | Easy | | | 0595 | [Big Countries](/solution/0500-0599/0595.Big%20Countries/README_EN.md) | `Database` | Easy | | | 0596 | [Classes More Than 5 Students](/solution/0500-0599/0596.Classes%20More%20Than%205%20Students/README_EN.md) | `Database` | Easy | | | 0597 | [Friend Requests I Overall Acceptance Rate](/solution/0500-0599/0597.Friend%20Requests%20I%20Overall%20Acceptance%20Rate/README_EN.md) | `Database` | Easy | π | | 0601 | [Human Traffic of Stadium](/solution/0600-0699/0601.Human%20Traffic%20of%20Stadium/README_EN.md) | `Database` | Hard | | | 0602 | [Friend Requests II Who Has the Most Friends](/solution/0600-0699/0602.Friend%20Requests%20II%20Who%20Has%20the%20Most%20Friends/README_EN.md) | `Database` | Medium | | | 0603 | [Consecutive Available Seats](/solution/0600-0699/0603.Consecutive%20Available%20Seats/README_EN.md) | `Database` | Easy | π | | 0607 | [Sales Person](/solution/0600-0699/0607.Sales%20Person/README_EN.md) | `Database` | Easy | | | 0608 | [Tree Node](/solution/0600-0699/0608.Tree%20Node/README_EN.md) | `Database` | Medium | | | 0610 | [Triangle Judgement](/solution/0600-0699/0610.Triangle%20Judgement/README_EN.md) | `Database` | Easy | | | 0612 | [Shortest Distance in a Plane](/solution/0600-0699/0612.Shortest%20Distance%20in%20a%20Plane/README_EN.md) | `Database` | Medium | π | | 0613 | [Shortest Distance in a Line](/solution/0600-0699/0613.Shortest%20Distance%20in%20a%20Line/README_EN.md) | `Database` | Easy | π | | 0614 | [Second Degree Follower](/solution/0600-0699/0614.Second%20Degree%20Follower/README_EN.md) | `Database` | Medium | π | | 0615 | [Average Salary Departments VS Company](/solution/0600-0699/0615.Average%20Salary%20Departments%20VS%20Company/README_EN.md) | `Database` | Hard | π | | 0618 | [Students Report By Geography](/solution/0600-0699/0618.Students%20Report%20By%20Geography/README_EN.md) | `Database` | Hard | π | | 0619 | [Biggest Single Number](/solution/0600-0699/0619.Biggest%20Single%20Number/README_EN.md) | `Database` | Easy | | | 0620 | [Not Boring Movies](/solution/0600-0699/0620.Not%20Boring%20Movies/README_EN.md) | `Database` | Easy | | | 0626 | [Exchange Seats](/solution/0600-0699/0626.Exchange%20Seats/README_EN.md) | `Database` | Medium | | | 0627 | [Swap Salary](/solution/0600-0699/0627.Swap%20Salary/README_EN.md) | `Database` | Easy | | | 1045 | [Customers Who Bought All Products](/solution/1000-1099/1045.Customers%20Who%20Bought%20All%20Products/README_EN.md) | `Database` | Medium | | | 1050 | [Actors and Directors Who Cooperated At Least Three Times](/solution/1000-1099/1050.Actors%20and%20Directors%20Who%20Cooperated%20At%20Least%20Three%20Times/README_EN.md) | `Database` | Easy | | | 1068 | [Product Sales Analysis I](/solution/1000-1099/1068.Product%20Sales%20Analysis%20I/README_EN.md) | `Database` | Easy | | | 1069 | [Product Sales Analysis II](/solution/1000-1099/1069.Product%20Sales%20Analysis%20II/README_EN.md) | `Database` | Easy | π | | 1070 | [Product Sales Analysis III](/solution/1000-1099/1070.Product%20Sales%20Analysis%20III/README_EN.md) | `Database` | Medium | | | 1075 | [Project Employees I](/solution/1000-1099/1075.Project%20Employees%20I/README_EN.md) | `Database` | Easy | | | 1076 | [Project Employees II](/solution/1000-1099/1076.Project%20Employees%20II/README_EN.md) | `Database` | Easy | π | | 1077 | [Project Employees III](/solution/1000-1099/1077.Project%20Employees%20III/README_EN.md) | `Database` | Medium | π | | 1082 | [Sales Analysis I](/solution/1000-1099/1082.Sales%20Analysis%20I/README_EN.md) | `Database` | Easy | π | | 1083 | [Sales Analysis II](/solution/1000-1099/1083.Sales%20Analysis%20II/README_EN.md) | `Database` | Easy | π | | 1084 | [Sales Analysis III](/solution/1000-1099/1084.Sales%20Analysis%20III/README_EN.md) | `Database` | Easy | | | 1097 | [Game Play Analysis V](/solution/1000-1099/1097.Game%20Play%20Analysis%20V/README_EN.md) | `Database` | Hard | π | | 1098 | [Unpopular Books](/solution/1000-1099/1098.Unpopular%20Books/README_EN.md) | `Database` | Medium | π | | 1107 | [New Users Daily Count](/solution/1100-1199/1107.New%20Users%20Daily%20Count/README_EN.md) | `Database` | Medium | π | | 1112 | [Highest Grade For Each Student](/solution/1100-1199/1112.Highest%20Grade%20For%20Each%20Student/README_EN.md) | `Database` | Medium | π | | 1113 | [Reported Posts](/solution/1100-1199/1113.Reported%20Posts/README_EN.md) | `Database` | Easy | π | | 1126 | [Active Businesses](/solution/1100-1199/1126.Active%20Businesses/README_EN.md) | `Database` | Medium | π | | 1127 | [User Purchase Platform](/solution/1100-1199/1127.User%20Purchase%20Platform/README_EN.md) | `Database` | Hard | π | | 1132 | [Reported Posts II](/solution/1100-1199/1132.Reported%20Posts%20II/README_EN.md) | `Database` | Medium | π | | 1141 | [User Activity for the Past 30 Days I](/solution/1100-1199/1141.User%20Activity%20for%20the%20Past%2030%20Days%20I/README_EN.md) | `Database` | Easy | | | 1142 | [User Activity for the Past 30 Days II](/solution/1100-1199/1142.User%20Activity%20for%20the%20Past%2030%20Days%20II/README_EN.md) | `Database` | Easy | π | | 1148 | [Article Views I](/solution/1100-1199/1148.Article%20Views%20I/README_EN.md) | `Database` | Easy | | | 1149 | [Article Views II](/solution/1100-1199/1149.Article%20Views%20II/README_EN.md) | `Database` | Medium | π | | 1158 | [Market Analysis I](/solution/1100-1199/1158.Market%20Analysis%20I/README_EN.md) | `Database` | Medium | | | 1159 | [Market Analysis II](/solution/1100-1199/1159.Market%20Analysis%20II/README_EN.md) | `Database` | Hard | π | | 1164 | [Product Price at a Given Date](/solution/1100-1199/1164.Product%20Price%20at%20a%20Given%20Date/README_EN.md) | `Database` | Medium | | | 1173 | [Immediate Food Delivery I](/solution/1100-1199/1173.Immediate%20Food%20Delivery%20I/README_EN.md) | `Database` | Easy | π | | 1174 | [Immediate Food Delivery II](/solution/1100-1199/1174.Immediate%20Food%20Delivery%20II/README_EN.md) | `Database` | Medium | | | 1179 | [Reformat Department Table](/solution/1100-1199/1179.Reformat%20Department%20Table/README_EN.md) | `Database` | Easy | | | 1193 | [Monthly Transactions I](/solution/1100-1199/1193.Monthly%20Transactions%20I/README_EN.md) | `Database` | Medium | | | 1194 | [Tournament Winners](/solution/1100-1199/1194.Tournament%20Winners/README_EN.md) | `Database` | Hard | π | | 1204 | [Last Person to Fit in the Bus](/solution/1200-1299/1204.Last%20Person%20to%20Fit%20in%20the%20Bus/README_EN.md) | `Database` | Medium | | | 1205 | [Monthly Transactions II](/solution/1200-1299/1205.Monthly%20Transactions%20II/README_EN.md) | `Database` | Medium | π | | 1211 | [Queries Quality and Percentage](/solution/1200-1299/1211.Queries%20Quality%20and%20Percentage/README_EN.md) | `Database` | Easy | | | 1212 | [Team Scores in Football Tournament](/solution/1200-1299/1212.Team%20Scores%20in%20Football%20Tournament/README_EN.md) | `Database` | Medium | π | | 1225 | [Report Contiguous Dates](/solution/1200-1299/1225.Report%20Contiguous%20Dates/README_EN.md) | `Database` | Hard | π | | 1241 | [Number of Comments per Post](/solution/1200-1299/1241.Number%20of%20Comments%20per%20Post/README_EN.md) | `Database` | Easy | π | | 1251 | [Average Selling Price](/solution/1200-1299/1251.Average%20Selling%20Price/README_EN.md) | `Database` | Easy | | | 1264 | [Page Recommendations](/solution/1200-1299/1264.Page%20Recommendations/README_EN.md) | `Database` | Medium | π | | 1270 | [All People Report to the Given Manager](/solution/1200-1299/1270.All%20People%20Report%20to%20the%20Given%20Manager/README_EN.md) | `Database` | Medium | π | | 1280 | [Students and Examinations](/solution/1200-1299/1280.Students%20and%20Examinations/README_EN.md) | `Database` | Easy | | | 1285 | [Find the Start and End Number of Continuous Ranges](/solution/1200-1299/1285.Find%20the%20Start%20and%20End%20Number%20of%20Continuous%20Ranges/README_EN.md) | `Database` | Medium | π | | 1294 | [Weather Type in Each Country](/solution/1200-1299/1294.Weather%20Type%20in%20Each%20Country/README_EN.md) | `Database` | Easy | π | | 1303 | [Find the Team Size](/solution/1300-1399/1303.Find%20the%20Team%20Size/README_EN.md) | `Database` | Easy | π | | 1308 | [Running Total for Different Genders](/solution/1300-1399/1308.Running%20Total%20for%20Different%20Genders/README_EN.md) | `Database` | Medium | π | | 1321 | [Restaurant Growth](/solution/1300-1399/1321.Restaurant%20Growth/README_EN.md) | `Database` | Medium | | | 1322 | [Ads Performance](/solution/1300-1399/1322.Ads%20Performance/README_EN.md) | `Database` | Easy | π | | 1327 | [List the Products Ordered in a Period](/solution/1300-1399/1327.List%20the%20Products%20Ordered%20in%20a%20Period/README_EN.md) | `Database` | Easy | | | 1336 | [Number of Transactions per Visit](/solution/1300-1399/1336.Number%20of%20Transactions%20per%20Visit/README_EN.md) | `Database` | Hard | π | | 1341 | [Movie Rating](/solution/1300-1399/1341.Movie%20Rating/README_EN.md) | `Database` | Medium | | | 1350 | [Students With Invalid Departments](/solution/1300-1399/1350.Students%20With%20Invalid%20Departments/README_EN.md) | `Database` | Easy | π | | 1355 | [Activity Participants](/solution/1300-1399/1355.Activity%20Participants/README_EN.md) | `Database` | Medium | π | | 1364 | [Number of Trusted Contacts of a Customer](/solution/1300-1399/1364.Number%20of%20Trusted%20Contacts%20of%20a%20Customer/README_EN.md) | `Database` | Medium | π | | 1369 | [Get the Second Most Recent Activity](/solution/1300-1399/1369.Get%20the%20Second%20Most%20Recent%20Activity/README_EN.md) | `Database` | Hard | π | | 1378 | [Replace Employee ID With The Unique Identifier](/solution/1300-1399/1378.Replace%20Employee%20ID%20With%20The%20Unique%20Identifier/README_EN.md) | `Database` | Easy | | | 1384 | [Total Sales Amount by Year](/solution/1300-1399/1384.Total%20Sales%20Amount%20by%20Year/README_EN.md) | `Database` | Hard | π | | 1393 | [Capital GainLoss](/solution/1300-1399/1393.Capital%20GainLoss/README_EN.md) | `Database` | Medium | | | 1398 | [Customers Who Bought Products A and B but Not C](/solution/1300-1399/1398.Customers%20Who%20Bought%20Products%20A%20and%20B%20but%20Not%20C/README_EN.md) | `Database` | Medium | π | | 1407 | [Top Travellers](/solution/1400-1499/1407.Top%20Travellers/README_EN.md) | `Database` | Easy | | | 1412 | [Find the Quiet Students in All Exams](/solution/1400-1499/1412.Find%20the%20Quiet%20Students%20in%20All%20Exams/README_EN.md) | `Database` | Hard | π | | 1421 | [NPV Queries](/solution/1400-1499/1421.NPV%20Queries/README_EN.md) | `Database` | Easy | π | | 1435 | [Create a Session Bar Chart](/solution/1400-1499/1435.Create%20a%20Session%20Bar%20Chart/README_EN.md) | `Database` | Easy | π | | 1440 | [Evaluate Boolean Expression](/solution/1400-1499/1440.Evaluate%20Boolean%20Expression/README_EN.md) | `Database` | Medium | π | | 1445 | [Apples & Oranges](/solution/1400-1499/1445.Apples%20%26%20Oranges/README_EN.md) | `Database` | Medium | π | | 1454 | [Active Users](/solution/1400-1499/1454.Active%20Users/README_EN.md) | `Database` | Medium | π | | 1459 | [Rectangles Area](/solution/1400-1499/1459.Rectangles%20Area/README_EN.md) | `Database` | Medium | π | | 1468 | [Calculate Salaries](/solution/1400-1499/1468.Calculate%20Salaries/README_EN.md) | `Database` | Medium | π | | 1479 | [Sales by Day of the Week](/solution/1400-1499/1479.Sales%20by%20Day%20of%20the%20Week/README_EN.md) | `Database` | Hard | π | | 1484 | [Group Sold Products By The Date](/solution/1400-1499/1484.Group%20Sold%20Products%20By%20The%20Date/README_EN.md) | `Database` | Easy | | | 1495 | [Friendly Movies Streamed Last Month](/solution/1400-1499/1495.Friendly%20Movies%20Streamed%20Last%20Month/README_EN.md) | `Database` | Easy | π | | 1501 | [Countries You Can Safely Invest In](/solution/1500-1599/1501.Countries%20You%20Can%20Safely%20Invest%20In/README_EN.md) | `Database` | Medium | π | | 1511 | [Customer Order Frequency](/solution/1500-1599/1511.Customer%20Order%20Frequency/README_EN.md) | `Database` | Easy | π | | 1517 | [Find Users With Valid E-Mails](/solution/1500-1599/1517.Find%20Users%20With%20Valid%20E-Mails/README_EN.md) | `Database` | Easy | | | 1527 | [Patients With a Condition](/solution/1500-1599/1527.Patients%20With%20a%20Condition/README_EN.md) | `Database` | Easy | | | 1532 | [The Most Recent Three Orders](/solution/1500-1599/1532.The%20Most%20Recent%20Three%20Orders/README_EN.md) | `Database` | Medium | π | | 1543 | [Fix Product Name Format](/solution/1500-1599/1543.Fix%20Product%20Name%20Format/README_EN.md) | `Database` | Easy | π | | 1549 | [The Most Recent Orders for Each Product](/solution/1500-1599/1549.The%20Most%20Recent%20Orders%20for%20Each%20Product/README_EN.md) | `Database` | Medium | π | | 1555 | [Bank Account Summary](/solution/1500-1599/1555.Bank%20Account%20Summary/README_EN.md) | `Database` | Medium | π | | 1565 | [Unique Orders and Customers Per Month](/solution/1500-1599/1565.Unique%20Orders%20and%20Customers%20Per%20Month/README_EN.md) | `Database` | Easy | π | | 1571 | [Warehouse Manager](/solution/1500-1599/1571.Warehouse%20Manager/README_EN.md) | `Database` | Easy | π | | 1581 | [Customer Who Visited but Did Not Make Any Transactions](/solution/1500-1599/1581.Customer%20Who%20Visited%20but%20Did%20Not%20Make%20Any%20Transactions/README_EN.md) | `Database` | Easy | | | 1587 | [Bank Account Summary II](/solution/1500-1599/1587.Bank%20Account%20Summary%20II/README_EN.md) | `Database` | Easy | | | 1596 | [The Most Frequently Ordered Products for Each Customer](/solution/1500-1599/1596.The%20Most%20Frequently%20Ordered%20Products%20for%20Each%20Customer/README_EN.md) | `Database` | Medium | π | | 1607 | [Sellers With No Sales](/solution/1600-1699/1607.Sellers%20With%20No%20Sales/README_EN.md) | `Database` | Easy | π | | 1613 | [Find the Missing IDs](/solution/1600-1699/1613.Find%20the%20Missing%20IDs/README_EN.md) | `Database` | Medium | π | | 1623 | [All Valid Triplets That Can Represent a Country](/solution/1600-1699/1623.All%20Valid%20Triplets%20That%20Can%20Represent%20a%20Country/README_EN.md) | `Database` | Easy | π | | 1633 | [Percentage of Users Attended a Contest](/solution/1600-1699/1633.Percentage%20of%20Users%20Attended%20a%20Contest/README_EN.md) | `Database` | Easy | | | 1635 | [Hopper Company Queries I](/solution/1600-1699/1635.Hopper%20Company%20Queries%20I/README_EN.md) | `Database` | Hard | π | | 1645 | [Hopper Company Queries II](/solution/1600-1699/1645.Hopper%20Company%20Queries%20II/README_EN.md) | `Database` | Hard | π | | 1651 | [Hopper Company Queries III](/solution/1600-1699/1651.Hopper%20Company%20Queries%20III/README_EN.md) | `Database` | Hard | π | | 1661 | [Average Time of Process per Machine](/solution/1600-1699/1661.Average%20Time%20of%20Process%20per%20Machine/README_EN.md) | `Database` | Easy | | | 1667 | [Fix Names in a Table](/solution/1600-1699/1667.Fix%20Names%20in%20a%20Table/README_EN.md) | `Database` | Easy | | | 1677 | [Product's Worth Over Invoices](/solution/1600-1699/1677.Product%27s%20Worth%20Over%20Invoices/README_EN.md) | `Database` | Easy | π | | 1683 | [Invalid Tweets](/solution/1600-1699/1683.Invalid%20Tweets/README_EN.md) | `Database` | Easy | | | 1693 | [Daily Leads and Partners](/solution/1600-1699/1693.Daily%20Leads%20and%20Partners/README_EN.md) | `Database` | Easy | | | 1699 | [Number of Calls Between Two Persons](/solution/1600-1699/1699.Number%20of%20Calls%20Between%20Two%20Persons/README_EN.md) | `Database` | Medium | π | | 1709 | [Biggest Window Between Visits](/solution/1700-1799/1709.Biggest%20Window%20Between%20Visits/README_EN.md) | `Database` | Medium | π | | 1715 | [Count Apples and Oranges](/solution/1700-1799/1715.Count%20Apples%20and%20Oranges/README_EN.md) | `Database` | Medium | π | | 1729 | [Find Followers Count](/solution/1700-1799/1729.Find%20Followers%20Count/README_EN.md) | `Database` | Easy | | | 1731 | [The Number of Employees Which Report to Each Employee](/solution/1700-1799/1731.The%20Number%20of%20Employees%20Which%20Report%20to%20Each%20Employee/README_EN.md) | `Database` | Easy | | | 1741 | [Find Total Time Spent by Each Employee](/solution/1700-1799/1741.Find%20Total%20Time%20Spent%20by%20Each%20Employee/README_EN.md) | `Database` | Easy | | | 1747 | [Leetflex Banned Accounts](/solution/1700-1799/1747.Leetflex%20Banned%20Accounts/README_EN.md) | `Database` | Medium | π | | 1757 | [Recyclable and Low Fat Products](/solution/1700-1799/1757.Recyclable%20and%20Low%20Fat%20Products/README_EN.md) | `Database` | Easy | | | 1767 | [Find the Subtasks That Did Not Execute](/solution/1700-1799/1767.Find%20the%20Subtasks%20That%20Did%20Not%20Execute/README_EN.md) | `Database` | Hard | π | | 1777 | [Product's Price for Each Store](/solution/1700-1799/1777.Product%27s%20Price%20for%20Each%20Store/README_EN.md) | `Database` | Easy | π | | 1783 | [Grand Slam Titles](/solution/1700-1799/1783.Grand%20Slam%20Titles/README_EN.md) | `Database` | Medium | π | | 1789 | [Primary Department for Each Employee](/solution/1700-1799/1789.Primary%20Department%20for%20Each%20Employee/README_EN.md) | `Database` | Easy | | | 1795 | [Rearrange Products Table](/solution/1700-1799/1795.Rearrange%20Products%20Table/README_EN.md) | `Database` | Easy | | | 1809 | [Ad-Free Sessions](/solution/1800-1899/1809.Ad-Free%20Sessions/README_EN.md) | `Database` | Easy | π | | 1811 | [Find Interview Candidates](/solution/1800-1899/1811.Find%20Interview%20Candidates/README_EN.md) | `Database` | Medium | π | | 1821 | [Find Customers With Positive Revenue this Year](/solution/1800-1899/1821.Find%20Customers%20With%20Positive%20Revenue%20this%20Year/README_EN.md) | `Database` | Easy | π | | 1831 | [Maximum Transaction Each Day](/solution/1800-1899/1831.Maximum%20Transaction%20Each%20Day/README_EN.md) | `Database` | Medium | π | | 1841 | [League Statistics](/solution/1800-1899/1841.League%20Statistics/README_EN.md) | `Database` | Medium | π | | 1843 | [Suspicious Bank Accounts](/solution/1800-1899/1843.Suspicious%20Bank%20Accounts/README_EN.md) | `Database` | Medium | π | | 1853 | [Convert Date Format](/solution/1800-1899/1853.Convert%20Date%20Format/README_EN.md) | `Database` | Easy | π | | 1867 | [Orders With Maximum Quantity Above Average](/solution/1800-1899/1867.Orders%20With%20Maximum%20Quantity%20Above%20Average/README_EN.md) | `Database` | Medium | π | | 1873 | [Calculate Special Bonus](/solution/1800-1899/1873.Calculate%20Special%20Bonus/README_EN.md) | `Database` | Easy | | | 1875 | [Group Employees of the Same Salary](/solution/1800-1899/1875.Group%20Employees%20of%20the%20Same%20Salary/README_EN.md) | `Database` | Medium | π | | 1890 | [The Latest Login in 2020](/solution/1800-1899/1890.The%20Latest%20Login%20in%202020/README_EN.md) | `Database` | Easy | | | 1892 | [Page Recommendations II](/solution/1800-1899/1892.Page%20Recommendations%20II/README_EN.md) | `Database` | Hard | π | | 1907 | [Count Salary Categories](/solution/1900-1999/1907.Count%20Salary%20Categories/README_EN.md) | `Database` | Medium | | | 1917 | [Leetcodify Friends Recommendations](/solution/1900-1999/1917.Leetcodify%20Friends%20Recommendations/README_EN.md) | `Database` | Hard | π | | 1919 | [Leetcodify Similar Friends](/solution/1900-1999/1919.Leetcodify%20Similar%20Friends/README_EN.md) | `Database` | Hard | π | | 1934 | [Confirmation Rate](/solution/1900-1999/1934.Confirmation%20Rate/README_EN.md) | `Database` | Medium | | | 1939 | [Users That Actively Request Confirmation Messages](/solution/1900-1999/1939.Users%20That%20Actively%20Request%20Confirmation%20Messages/README_EN.md) | `Database` | Easy | π | | 1949 | [Strong Friendship](/solution/1900-1999/1949.Strong%20Friendship/README_EN.md) | `Database` | Medium | π | | 1951 | [All the Pairs With the Maximum Number of Common Followers](/solution/1900-1999/1951.All%20the%20Pairs%20With%20the%20Maximum%20Number%20of%20Common%20Followers/README_EN.md) | `Database` | Medium | π | | 1965 | [Employees With Missing Information](/solution/1900-1999/1965.Employees%20With%20Missing%20Information/README_EN.md) | `Database` | Easy | | | 1972 | [First and Last Call On the Same Day](/solution/1900-1999/1972.First%20and%20Last%20Call%20On%20the%20Same%20Day/README_EN.md) | `Database` | Hard | π | | 1978 | [Employees Whose Manager Left the Company](/solution/1900-1999/1978.Employees%20Whose%20Manager%20Left%20the%20Company/README_EN.md) | `Database` | Easy | | | 1988 | [Find Cutoff Score for Each School](/solution/1900-1999/1988.Find%20Cutoff%20Score%20for%20Each%20School/README_EN.md) | `Database` | Medium | π | | 1990 | [Count the Number of Experiments](/solution/1900-1999/1990.Count%20the%20Number%20of%20Experiments/README_EN.md) | `Database` | Medium | π | | 2004 | [The Number of Seniors and Juniors to Join the Company](/solution/2000-2099/2004.The%20Number%20of%20Seniors%20and%20Juniors%20to%20Join%20the%20Company/README_EN.md) | `Database` | Hard | π | | 2010 | [The Number of Seniors and Juniors to Join the Company II](/solution/2000-2099/2010.The%20Number%20of%20Seniors%20and%20Juniors%20to%20Join%20the%20Company%20II/README_EN.md) | `Database` | Hard | π | | 2020 | [Number of Accounts That Did Not Stream](/solution/2000-2099/2020.Number%20of%20Accounts%20That%20Did%20Not%20Stream/README_EN.md) | `Database` | Medium | π | | 2026 | [Low-Quality Problems](/solution/2000-2099/2026.Low-Quality%20Problems/README_EN.md) | `Database` | Easy | π | | 2041 | [Accepted Candidates From the Interviews](/solution/2000-2099/2041.Accepted%20Candidates%20From%20the%20Interviews/README_EN.md) | `Database` | Medium | π | | 2051 | [The Category of Each Member in the Store](/solution/2000-2099/2051.The%20Category%20of%20Each%20Member%20in%20the%20Store/README_EN.md) | `Database` | Medium | π | | 2066 | [Account Balance](/solution/2000-2099/2066.Account%20Balance/README_EN.md) | `Database` | Medium | π | | 2072 | [The Winner University](/solution/2000-2099/2072.The%20Winner%20University/README_EN.md) | `Database` | Easy | π | | 2082 | [The Number of Rich Customers](/solution/2000-2099/2082.The%20Number%20of%20Rich%20Customers/README_EN.md) | `Database` | Easy | π | | 2084 | [Drop Type 1 Orders for Customers With Type 0 Orders](/solution/2000-2099/2084.Drop%20Type%201%20Orders%20for%20Customers%20With%20Type%200%20Orders/README_EN.md) | `Database` | Medium | π | | 2112 | [The Airport With the Most Traffic](/solution/2100-2199/2112.The%20Airport%20With%20the%20Most%20Traffic/README_EN.md) | `Database` | Medium | π | | 2118 | [Build the Equation](/solution/2100-2199/2118.Build%20the%20Equation/README_EN.md) | `Database` | Hard | π | | 2142 | [The Number of Passengers in Each Bus I](/solution/2100-2199/2142.The%20Number%20of%20Passengers%20in%20Each%20Bus%20I/README_EN.md) | `Database` | Medium | π | | 2153 | [The Number of Passengers in Each Bus II](/solution/2100-2199/2153.The%20Number%20of%20Passengers%20in%20Each%20Bus%20II/README_EN.md) | `Database` | Hard | π | | 2159 | [Order Two Columns Independently](/solution/2100-2199/2159.Order%20Two%20Columns%20Independently/README_EN.md) | `Database` | Medium | π | | 2173 | [Longest Winning Streak](/solution/2100-2199/2173.Longest%20Winning%20Streak/README_EN.md) | `Database` | Hard | π | | 2175 | [The Change in Global Rankings](/solution/2100-2199/2175.The%20Change%20in%20Global%20Rankings/README_EN.md) | `Database` | Medium | π | | 2199 | [Finding the Topic of Each Post](/solution/2100-2199/2199.Finding%20the%20Topic%20of%20Each%20Post/README_EN.md) | `Database` | Hard | π | | 2205 | [The Number of Users That Are Eligible for Discount](/solution/2200-2299/2205.The%20Number%20of%20Users%20That%20Are%20Eligible%20for%20Discount/README_EN.md) | `Database` | Easy | π | | 2228 | [Users With Two Purchases Within Seven Days](/solution/2200-2299/2228.Users%20With%20Two%20Purchases%20Within%20Seven%20Days/README_EN.md) | `Database` | Medium | π | | 2230 | [The Users That Are Eligible for Discount](/solution/2200-2299/2230.The%20Users%20That%20Are%20Eligible%20for%20Discount/README_EN.md) | `Database` | Easy | π | | 2238 | [Number of Times a Driver Was a Passenger](/solution/2200-2299/2238.Number%20of%20Times%20a%20Driver%20Was%20a%20Passenger/README_EN.md) | `Database` | Medium | π | | 2252 | [Dynamic Pivoting of a Table](/solution/2200-2299/2252.Dynamic%20Pivoting%20of%20a%20Table/README_EN.md) | `Database` | Hard | π | | 2253 | [Dynamic Unpivoting of a Table](/solution/2200-2299/2253.Dynamic%20Unpivoting%20of%20a%20Table/README_EN.md) | `Database` | Hard | π | | 2292 | [Products With Three or More Orders in Two Consecutive Years](/solution/2200-2299/2292.Products%20With%20Three%20or%20More%20Orders%20in%20Two%20Consecutive%20Years/README_EN.md) | `Database` | Medium | π | | 2298 | [Tasks Count in the Weekend](/solution/2200-2299/2298.Tasks%20Count%20in%20the%20Weekend/README_EN.md) | `Database` | Medium | π | | 2308 | [Arrange Table by Gender](/solution/2300-2399/2308.Arrange%20Table%20by%20Gender/README_EN.md) | `Database` | Medium | π | | 2314 | [The First Day of the Maximum Recorded Degree in Each City](/solution/2300-2399/2314.The%20First%20Day%20of%20the%20Maximum%20Recorded%20Degree%20in%20Each%20City/README_EN.md) | `Database` | Medium | π | | 2324 | [Product Sales Analysis IV](/solution/2300-2399/2324.Product%20Sales%20Analysis%20IV/README_EN.md) | `Database` | Medium | π | | 2329 | [Product Sales Analysis V](/solution/2300-2399/2329.Product%20Sales%20Analysis%20V/README_EN.md) | `Database` | Easy | π | | 2339 | [All the Matches of the League](/solution/2300-2399/2339.All%20the%20Matches%20of%20the%20League/README_EN.md) | `Database` | Easy | π | | 2346 | [Compute the Rank as a Percentage](/solution/2300-2399/2346.Compute%20the%20Rank%20as%20a%20Percentage/README_EN.md) | `Database` | Medium | π | | 2356 | [Number of Unique Subjects Taught by Each Teacher](/solution/2300-2399/2356.Number%20of%20Unique%20Subjects%20Taught%20by%20Each%20Teacher/README_EN.md) | `Database` | Easy | | | 2362 | [Generate the Invoice](/solution/2300-2399/2362.Generate%20the%20Invoice/README_EN.md) | `Database` | Hard | π | | 2372 | [Calculate the Influence of Each Salesperson](/solution/2300-2399/2372.Calculate%20the%20Influence%20of%20Each%20Salesperson/README_EN.md) | `Database` | Medium | π | | 2377 | [Sort the Olympic Table](/solution/2300-2399/2377.Sort%20the%20Olympic%20Table/README_EN.md) | `Database` | Easy | π | | 2388 | [Change Null Values in a Table to the Previous Value](/solution/2300-2399/2388.Change%20Null%20Values%20in%20a%20Table%20to%20the%20Previous%20Value/README_EN.md) | `Database` | Medium | π | | 2394 | [Employees With Deductions](/solution/2300-2399/2394.Employees%20With%20Deductions/README_EN.md) | `Database` | Medium | π | | 2474 | [Customers With Strictly Increasing Purchases](/solution/2400-2499/2474.Customers%20With%20Strictly%20Increasing%20Purchases/README_EN.md) | `Database` | Hard | π | | 2480 | [Form a Chemical Bond](/solution/2400-2499/2480.Form%20a%20Chemical%20Bond/README_EN.md) | `Database` | Easy | π | | 2494 | [Merge Overlapping Events in the Same Hall](/solution/2400-2499/2494.Merge%20Overlapping%20Events%20in%20the%20Same%20Hall/README_EN.md) | `Database` | Hard | π | | 2504 | [Concatenate the Name and the Profession](/solution/2500-2599/2504.Concatenate%20the%20Name%20and%20the%20Profession/README_EN.md) | `Database` | Easy | π | | 2668 | [Find Latest Salaries](/solution/2600-2699/2668.Find%20Latest%20Salaries/README_EN.md) | `Database` | Easy | π | | 2669 | [Count Artist Occurrences On Spotify Ranking List](/solution/2600-2699/2669.Count%20Artist%20Occurrences%20On%20Spotify%20Ranking%20List/README_EN.md) | `Database` | Easy | π | | 2686 | [Immediate Food Delivery III](/solution/2600-2699/2686.Immediate%20Food%20Delivery%20III/README_EN.md) | `Database` | Medium | π | | 2687 | [Bikes Last Time Used](/solution/2600-2699/2687.Bikes%20Last%20Time%20Used/README_EN.md) | `Database` | Easy | π | | 2688 | [Find Active Users](/solution/2600-2699/2688.Find%20Active%20Users/README_EN.md) | `Database` | Medium | π | | 2701 | [Consecutive Transactions with Increasing Amounts](/solution/2700-2799/2701.Consecutive%20Transactions%20with%20Increasing%20Amounts/README_EN.md) | `Database` | Hard | π | | 2720 | [Popularity Percentage](/solution/2700-2799/2720.Popularity%20Percentage/README_EN.md) | `Database` | Hard | π | | 2738 | [Count Occurrences in Text](/solution/2700-2799/2738.Count%20Occurrences%20in%20Text/README_EN.md) | `Database` | Medium | π | | 2752 | [Customers with Maximum Number of Transactions on Consecutive Days](/solution/2700-2799/2752.Customers%20with%20Maximum%20Number%20of%20Transactions%20on%20Consecutive%20Days/README_EN.md) | `Database` | Hard | π | | 2783 | [Flight Occupancy and Waitlist Analysis](/solution/2700-2799/2783.Flight%20Occupancy%20and%20Waitlist%20Analysis/README_EN.md) | `Database` | Medium | π | | 2793 | [Status of Flight Tickets](/solution/2700-2799/2793.Status%20of%20Flight%20Tickets/README_EN.md) | | Hard | π | | 2820 | [Election Results](/solution/2800-2899/2820.Election%20Results/README_EN.md) | | Medium | π | | 2837 | [Total Traveled Distance](/solution/2800-2899/2837.Total%20Traveled%20Distance/README_EN.md) | `Database` | Easy | π | | 2853 | [Highest Salaries Difference](/solution/2800-2899/2853.Highest%20Salaries%20Difference/README_EN.md) | `Database` | Easy | π | | 2854 | [Rolling Average Steps](/solution/2800-2899/2854.Rolling%20Average%20Steps/README_EN.md) | `Database` | Medium | π | | 2893 | [Calculate Orders Within Each Interval](/solution/2800-2899/2893.Calculate%20Orders%20Within%20Each%20Interval/README_EN.md) | `Database` | Medium | π | | 2922 | [Market Analysis III](/solution/2900-2999/2922.Market%20Analysis%20III/README_EN.md) | `Database` | Medium | π | | 2978 | [Symmetric Coordinates](/solution/2900-2999/2978.Symmetric%20Coordinates/README_EN.md) | `Database` | Medium | π | | 2984 | [Find Peak Calling Hours for Each City](/solution/2900-2999/2984.Find%20Peak%20Calling%20Hours%20for%20Each%20City/README_EN.md) | `Database` | Medium | π | | 2985 | [Calculate Compressed Mean](/solution/2900-2999/2985.Calculate%20Compressed%20Mean/README_EN.md) | `Database` | Easy | π | | 2986 | [Find Third Transaction](/solution/2900-2999/2986.Find%20Third%20Transaction/README_EN.md) | `Database` | Medium | π | | 2987 | [Find Expensive Cities](/solution/2900-2999/2987.Find%20Expensive%20Cities/README_EN.md) | `Database` | Easy | π | | 2988 | [Manager of the Largest Department](/solution/2900-2999/2988.Manager%20of%20the%20Largest%20Department/README_EN.md) | `Database` | Medium | π | | 2989 | [Class Performance](/solution/2900-2999/2989.Class%20Performance/README_EN.md) | `Database` | Medium | π | | 2990 | [Loan Types](/solution/2900-2999/2990.Loan%20Types/README_EN.md) | `Database` | Easy | π | | 2991 | [Top Three Wineries](/solution/2900-2999/2991.Top%20Three%20Wineries/README_EN.md) | `Database` | Hard | π | | 2993 | [Friday Purchases I](/solution/2900-2999/2993.Friday%20Purchases%20I/README_EN.md) | `Database` | Medium | π | | 2994 | [Friday Purchases II](/solution/2900-2999/2994.Friday%20Purchases%20II/README_EN.md) | `Database` | Hard | π | | 2995 | [Viewers Turned Streamers](/solution/2900-2999/2995.Viewers%20Turned%20Streamers/README_EN.md) | `Database` | Hard | π | | 3050 | [Pizza Toppings Cost Analysis](/solution/3000-3099/3050.Pizza%20Toppings%20Cost%20Analysis/README_EN.md) | `Database` | Medium | π | | 3051 | [Find Candidates for Data Scientist Position](/solution/3000-3099/3051.Find%20Candidates%20for%20Data%20Scientist%20Position/README_EN.md) | `Database` | Easy | π | | 3052 | [Maximize Items](/solution/3000-3099/3052.Maximize%20Items/README_EN.md) | `Database` | Hard | π | | 3053 | [Classifying Triangles by Lengths](/solution/3000-3099/3053.Classifying%20Triangles%20by%20Lengths/README_EN.md) | `Database` | Easy | π | | 3054 | [Binary Tree Nodes](/solution/3000-3099/3054.Binary%20Tree%20Nodes/README_EN.md) | `Database` | Medium | π | | 3055 | [Top Percentile Fraud](/solution/3000-3099/3055.Top%20Percentile%20Fraud/README_EN.md) | `Database` | Medium | π | | 3056 | [Snaps Analysis](/solution/3000-3099/3056.Snaps%20Analysis/README_EN.md) | `Database` | Medium | π | | 3057 | [Employees Project Allocation](/solution/3000-3099/3057.Employees%20Project%20Allocation/README_EN.md) | `Database` | Hard | π | | 3058 | [Friends With No Mutual Friends](/solution/3000-3099/3058.Friends%20With%20No%20Mutual%20Friends/README_EN.md) | `Database` | Medium | π | | 3059 | [Find All Unique Email Domains](/solution/3000-3099/3059.Find%20All%20Unique%20Email%20Domains/README_EN.md) | `Database` | Easy | π | | 3060 | [User Activities within Time Bounds](/solution/3000-3099/3060.User%20Activities%20within%20Time%20Bounds/README_EN.md) | `Database` | Hard | π | | 3061 | [Calculate Trapping Rain Water](/solution/3000-3099/3061.Calculate%20Trapping%20Rain%20Water/README_EN.md) | `Database` | Hard | π | | 3087 | [Find Trending Hashtags](/solution/3000-3099/3087.Find%20Trending%20Hashtags/README_EN.md) | `Database` | Medium | π | | 3089 | [Find Bursty Behavior](/solution/3000-3099/3089.Find%20Bursty%20Behavior/README_EN.md) | `Database` | Medium | π | | 3103 | [Find Trending Hashtags II](/solution/3100-3199/3103.Find%20Trending%20Hashtags%20II/README_EN.md) | `Database` | Hard | π | | 3118 | [Friday Purchase III](/solution/3100-3199/3118.Friday%20Purchase%20III/README_EN.md) | `Database` | Medium | π | | 3124 | [Find Longest Calls](/solution/3100-3199/3124.Find%20Longest%20Calls/README_EN.md) | `Database` | Medium | π | | 3126 | [Server Utilization Time](/solution/3100-3199/3126.Server%20Utilization%20Time/README_EN.md) | `Database` | Medium | π | | 3140 | [Consecutive Available Seats II](/solution/3100-3199/3140.Consecutive%20Available%20Seats%20II/README_EN.md) | `Database` | Medium | π | | 3150 | [Invalid Tweets II](/solution/3100-3199/3150.Invalid%20Tweets%20II/README_EN.md) | | Easy | π | ## Copyright The copyright of this project belongs to [Doocs](https://github.com/doocs) community. For commercial reprints, please contact [@yanglbme](mailto:contact@yanglibin.info) for authorization. For non-commercial reprints, please indicate the source. ## Contact Us We welcome everyone to add @yanglbme's personal WeChat (WeChat ID: YLB0109), with the note "leetcode". In the future, we will create algorithm and technology related discussion groups, where we can learn and share experiences together, and make progress together. | <img src="https://cdn-doocs.oss-cn-shenzhen.aliyuncs.com/gh/doocs/images/qrcode-for-yanglbme-en.png" width="260px" align="left"/> | | --------------------------------------------------------------------------------------------------------------------------------- | ## License This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/">Creative Commons Attribution-ShareAlike 4.0 International License</a>.