Database

📄️ 175. Combine Two Tables

Write a solution to report the first name, last name, city, and state of each person in the `Person` table. If the address of a `personId` is not present in the `Address` table, report null instead.

📄️ 176. Second Highest Salary

Write a solution to find the second highest salary from the `Employee` table. If there is no second highest salary, return `null` (return `None` in Pandas).

📄️ 177. Nth Highest Salary

Write a solution to find the nth highest salary from the `Employee` table. If there is no nth highest salary, return `null`.

📄️ 178. Rank Scores

Write a solution to find the rank of the scores.

📄️ 181. Employees Earning More Than Their Managers

Write a solution to find the employees who earn more than their managers.

📄️ 182. Duplicate Emails

Write a solution to report all the duplicate emails. Note that it's guaranteed that the email field is not `NULL`.

📄️ 183. Customers Who Never Order

Write a solution to find all customers who never order anything.

📄️ 196. Delete Duplicate Emails

Write a solution to delete all duplicate emails, keeping only one unique email with the smallest id. After running your script, the answer shown is the `Person` table. The driver will first compile and run your piece of code and then show the `Person` table. The final order of the `Person` table does not matter.