README.md

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	-