Leetcode SQL

196. Delete Duplicate Emails

Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.

+----+------------------+
| Id | Email            |
+----+------------------+
| 1  |…

Leetcode SQL

570. Managers with at Least 5 Direct Reports

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 	  |Department…

Leetcode SQL

571. Find Median Given Frequency of Numbers

The Numbers table keeps the value of number and its frequency.

+----------+-------------+
|  Number  |  Frequency  |
+----------+-------------|
|  0       |  7          |
|  1       |  1          |
|  2       |…

Leetcode SQL

185. Department Top Three Salaries

The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id.

+----+-------+--------+--------------+
| Id | Name  | Salary | DepartmentId |…

Leetcode SQL

184. Department Highest Salary

The Employee table holds all employees. Every employee has an Id, a salary, and there is also a column for the department Id.

+----+-------+--------+--------------+
| Id | Name  | Salary | DepartmentId |…

Leetcode Algorithms

569. Median Employee Salary

The Employee table holds all employees. The employee table has three columns: Employee Id, Company Name, and Salary.

+-----+------------+--------+
|Id   | Company    | Salary |
+-----+------------+--------+
|1    |…

Leetcode SQL

197. Rising Temperature

Table: Weather

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| id            | int     |
| recordDate    | date    |
| temperature   | int     |
+---------------+---------+
id is the primary…

Leetcode SQL

262. Trips and Users

The Trips table holds all taxi trips. Each trip has a unique Id, while Client_Id and Driver_Id are both foreign keys to the Users_Id at the Users table. Status is an ENUM type of (‘completed’, ‘cancelled_by_driver’, ‘cancelled_by_client’).