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Exchange Seats description: Mary is a teacher in a middle school and she has a table seat storing students’ names and their corresponding seat ids. The column id is continuous increment. Mary wants to...

Rising Temperature description: Given a Weather table, write a SQL query to find all dates’ Ids with higher temperature compared to its previous (yesterday’s) dates. +---------+------------------+---...

Delete Duplicate Emails description: Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. +----+------------------+ | I...

Department Top Three Salaries description: The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id. +----+-------+--------+--------------+ |...

Second Highest Salary Write a SQL query to get the second highest salary from the Employee table. +----+--------+ | Id | Salary | +----+--------+ | 1 | 100 | | 2 | 200 | | 3 | 300 | +----+...

[Combine Two Tables] Table: Person +-------------+---------+ | Column Name | Type | +-------------+---------+ | PersonId | int | | FirstName | varchar | | LastName | varchar | +--------...