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Solved SQL questions in the second round. Aim to organize Multiple solutions and thoughts for each question, compare and find the optimal ones.

Multiple-Solutions-for-Leetcode-Problems

There will be TWO ways to distribute the sql solutions:

  1. By questions' category - the folders above
  2. By questions' function - the lists below

Missing value or not exist

Return and state as "null"
# 1378. Replace Employee ID With The Unique Identi.sql -
Return and state as 0
# 1142. User Activity for the Past 30 Days II.sql # 1322. Ads Performance.sql
# 1241. Number of Comments per Post.sql # 1407. Top Travellers.sql
Return the related column value
# 1350. Students With Invalid Departments.sql # 607. Sales Person.sql
# 1083. Sales Analysis II.sql # 1084. Sales Analysis III.sql

Exist / Sub-query

# 1549. The Most Recent Orders for Each Product.sql # 1532. The Most Recent Three Orders.sql

Aggregate

Most/Top
# 1596. The Most Frequently Ordered Products.sql # 1082. Sales Analysis I.sql
# 1076. Project Employees II.sql # 586. Customer Placing the Largest NO of Order.sql
# 619. Biggest Single Number.sql -
Return result, and result will be compared "more/less than"
# 1587. Bank Account Summary II.sql -
As a condition, the result will be compared "more/less than" or "have/not have
# 1511. Customer Order Frequency.sql # 1050. Actors and Directors Who Cooperated.sql
# 1327. List the Products Ordered in a Period.sql # 1083. Sales Analysis II.sql
# 1398. Customers Who Bought Products A B not C.sql # 1501. Countries You Can Safely Invest In.sql
return categories from numbers
# 1294. Weather Type in Each Country.sql -
Include the result, no matter is 0 or not
# 1280. Students and Examinations.sql -
Others
# 1303. Find the Team Size.sql -

Calculation

Plus and Minus transaction
# 1555. Bank Account Summary.sql # 1445. Apples & Oranges.sql
Rate or Percentage
# 1322. Ads Performance.sql # 1251. Average Selling Price.sql
# 1211. Queries Quality and Percentage.sql # 1173. Immediate Food Delivery I.sql
across two or more tables
# 1571. Warehouse Manager.sql -
odd number
# 620. Not Boring Movies.sql -
Consecutive Problems
# 603. Consecutive Available Seats.sql # 1454. Active Users.sql
Others
# 613. Shortest Distance in a Line.sql -
Mathematical shape
# 1459. Rectangles Area.sql -

Date

Find a specific month
# 1511. Customer Order Frequency.sql # 1294. Weather Type in Each Country.sql
Find a specific date/time period
# 1113. Reported Posts.sql # 1141. User Activity for the Past 30 Days I.sql
# 1084. Sales Analysis III.sql # 1251. Average Selling Price.sql
# 1454. Active Users.sql -
Modify into a specific format
# 1543. Fix Product Name Format.sql # 1565. Unique Orders and Customers Per Month.sql
Most recent date / first date
# 1549. The Most Recent Orders for Each Product.sql # 511. Game Play Analysis I.sql
# 1532. The Most Recent Three Orders.sql -

Case by case

# 1294. Weather Type in Each Country.sql # 1322. Ads Performance.sql
# 627. Swap Salary.sql # 610. Triangle Judgement.sql
Boolean
# 1440. Evaluate Boolean Expression.sql -

Joins

Three tables
# 1555. Bank Account Summary.sql # 1280. Students and Examinations.sql
# 1440. Evaluate Boolean Expression.sql # 1501. Countries You Can Safely Invest In.sql
# 1468. Calculate Salaries.sql -
Self Joins
# 1241. Number of Comments per Post.sql -

Formating

aggregate the product names in one cell
# 1484. Group Sold Products By The Date.sql -
String Validation
# 1517. Find Users With Valid E-Mails.sql -
  • Beginning of the string
  • Any upper/lower case chars
  • No. of chars
  • Range
  • accept chars
  • end with
String Formay - No lowercase without leading or trailing white spaces
# 1543. Fix Product Name Format.sql -

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verified publisher icon Qian-Yu-2020

Metadata

Solved SQL questions in the second round. Aim to organize Multiple solutions and thoughts for each question, compare and find the optimal ones.

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