Week 7-8: 4 Sql Questions per day (Week 7-8), 40 LC Quest
[Easy + Medium]

|22/08/2023| Very Easy: single select |
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|==Finished==|1757. Recyclable and Low Fat Products|
|==Finished==|627. Swap Salary|
|==Finished==|595. Big Countries|
|==Finished==|584. Find Customer Referee|
|==Finished==|1693. Daily Leads and Partners|
|==Finished==|197. Rising Temperature(用到interval day)|

### Easy: single select + where + group by, order by

|23/08/2023|Question |
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|==Finished==| 1527. Patients With a Condition
|==Finished==|1587. Bank Account Summary II
|==Finished==|1484. Group Sold Products By The Date (GROUP_CONCAT)
|==Finished==|1890. The Latest Login in 2020

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|24/08/2023|Question |
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|-| 1251. Average Selling Price
|==Finished==| 1204. Last Person to Fit in the Bus
|-| 183. Customers Who Never Order
|==Finished==| 1075. Project Employees I

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|25/08/2023|Question |
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|-| ==Medium== 1045. Customers Who Bought All Products
|-|1633. Percentage of Users Attended a Contest
|-|619. Biggest Single Number
|==Finished==|1321. Restaurant Growth
|==Finished==| 620. Not Boring Movies (MOD)

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|28/08/2023|Question |
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|-|1141. User Activity for the Past 30 Days I (interval day)
|-|1084. Sales Analysis III
|-| 2082. The Number of Rich Customers

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|29/08/2023|Tricky question |
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|==Finished==| ==Medium== 585. Investments in 2016
|==Finished==|1173. Immediate Food Delivery I
|==Finished==| ==Midium== 1174. Immediate Food Delivery II
|-|==Midium==1393. Capital Gain/Loss
|-|1378. Replace Employee ID With The Unique Identifier
|-|1795. Rearrange Products Table
|-|==Midium== 602. Friend Requests II: Who Has the Most Friends

### Medium: inner join/ left join/ union, etc
|30/08/2023|Question |
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|-|1789. Primary Department for Each Employee
|-| 1965. Employees With Missing Information

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|31/08/2023|Question |
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|==Finished==|1148. Article Views I
|==Finished==| 175. Combine Two Tables
|==Finished==| 1517. Find Users With Valid E-Mails (用到sql regexp)
|==Finished==|==Midium== 608. Tree Node

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|06/09/2023|Question |
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|==Finished==| 1581. Customer Who Visited but Did Not Make Any Transactions
|==Finished==| <font color="#f00">Hard </font>185. Department Top Three Salaries

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|07/09/2023|Question |
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|==Finished==|570. Managers with at Least 5 Direct Reports
|-|1661. Average Time of Process per Machine
|-|==Midium== 1934. Confirmation Rate
|-|577. Employee Bonus
|-|181. Employees Earning More Than Their Managers
|-| 1158. Market Analysis I

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|08/09/2023|Question |
|-|-|
|-|607. Sales Person
|-|1211. Queries Quality and Percentage
|-|==Midium==626. Exchange Seats
|-|586. Customer Placing the Largest Number of Orders
|-|-|
|-|1280. Students and Examinations
|-|==Midium==1193. Monthly Transactions I
|-|==Midium==1164. Product Price at a Given Date
|-|==Midium==1907. Count Salary Categories
|-|1873. Calculate Special Bonus
|-|-|
|-|==Midium== 184. Department Highest Salary
|-|==Midium== 1341. Movie Rating
|-| <font color="#f00">Hard </font> 601. Human Traffic of Stadium
|-|1978. Employees Whose Manager Left the Company
|-| 1731. The Number of Employees Which Report to Each Employee
|-|==Midium== 550. Game Play Analysis IV
|-|==Midium== 176. Second Highest Salary