LeetCode 619: Biggest Single Number
A SQL guide for finding the largest number that appears exactly once in a table.
Tag
Group-By
17 notes
LeetCode 618: Students Report By Geography
A SQL guide for pivoting rows into columns using ranking and conditional aggregation.
LeetCode 615: Average Salary: Departments VS Company
A SQL guide for comparing each department's monthly average salary against the company's monthly average salary.
LeetCode 614: Second Degree Follower
A SQL guide for finding users who both follow someone and have followers, then counting how many followers they have.
LeetCode 602: Friend Requests II: Who Has the Most Friends
A SQL guide for counting friendships from both requester and accepter sides, then returning the user with the most friends.
LeetCode 512: Game Play Analysis II
A clear explanation of finding the first device used by each player using SQL aggregation and a join.
LeetCode 511: Game Play Analysis I
A clear explanation of finding each player's first login date using SQL aggregation.
LeetCode 596: Classes With at Least 5 Students
A clear SQL guide for finding classes that have at least five students.
LeetCode 586: Customer Placing the Largest Number of Orders
A clear SQL guide for finding the customer who placed the most orders.
LeetCode 585: Investments in 2016
A clear SQL guide for summing 2016 investments for policies with repeated 2015 investment values and unique locations.
LeetCode 580: Count Student Number in Departments
A clear SQL guide for counting students in every department, including departments with zero students.
LeetCode 578: Get Highest Answer Rate Question
A clear SQL guide for finding the question with the highest answer rate from survey logs.
LeetCode 574: Winning Candidate
A clear explanation of Winning Candidate using SQL aggregation to count votes and return the candidate with the most votes.
LeetCode 570: Managers with at Least 5 Direct Reports
A clear explanation of Managers with at Least 5 Direct Reports using grouping and a self join.
LeetCode 262: Trips and Users
A clear explanation of the Trips and Users SQL problem using joins, filtering, grouping, and conditional aggregation.
LeetCode 184: Department Highest Salary
A clear SQL solution for finding every employee who earns the highest salary in their department.
LeetCode 182: Duplicate Emails
A clear SQL solution for reporting email values that appear more than once in the Person table.