LeetCode Customers Who Never Order
Problem Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything. Table: Customers. +----+-------+ |...
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LeetCode Duplicate Emails
Problem Write a SQL query to find all duplicate emails in a table named Person. +----+---------+ | Id | Email | +----+---------+ | 1 | a@b.com | | 2 | c@d.com | | 3 | a@b.com | +----+-------...
LeetCode Employees Earning More Than Their Managers
Problem The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id. +----+-------+--------+-----------+ | Id | Name ...
LeetCode Nth Highest Salary
Problem Write a SQL query to get the nth highest salary from the Employee table. +----+--------+ | Id | Salary | +----+--------+ | 1 | 100 | | 2 | 200 | | 3 | 300 | +----+--------+ F...
LeetCode Second Highest Salary
Problem Write a SQL query to get the second highest salary from the Employee table. +----+--------+ | Id | Salary | +----+--------+ | 1 | 100 | | 2 | 200 | | 3 | 300 | +----+--------+...
LeetCode Combine Two Tables
Problem Table: Person +-------------+---------+ | Column Name | Type | +-------------+---------+ | PersonId | int | | FirstName | varchar | | LastName | varchar | +-------------+--...
LeetCode Factorial Trailing Zeroes
Problem Given an integer n, return the number of trailing zeroes in n!. Note: Your solution should be in logarithmic time complexity. 即计算n!末尾0的个数。要求用对数时间复杂度 Python 实现 # Given an integer n, r...
LeetCode Excel Sheet Column Number
Problem Related to question Excel Sheet Column Title Given a column title as appear in an Excel sheet, return its corresponding column number. For example: A -> 1 B -> 2 C ->...
LeetCode Majority Element
Problem Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority ...
LeetCode Excel Sheet Column Title
Problem Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example: 1 -> A 2 -> B 3 -> C ... 26 -> Z 27 -> AA...