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题目：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 |

QuestionIn social network like Facebook or Twitter, people send friend requests and accept others' requests as well.Table request_accepted holds the data of friend acceptance, while requester_

题目X city opened a new cinema, many people would like to go to this cinema. The cinema also gives out a poster indicating the movies’ ratings and descriptions.Please write a SQL query to output

Given a table salary, such as the one below, that has m=male and f=female values. Swap all f and m values (i.e., change all f values to m and vice versa) with a single update query and no intermedia

https://leetcode.com/articles/tree-node/懒得粘过来了学习一下case then和if语句神奇的sql

Write a SQL query to find all numbers that appear at least three times consecutively.+----+-----+| Id | Num |+----+-----+| 1 | 1 || 2 | 1 || 3 | 1 || 4 | 2 || 5 | 1 || 6 | 2

QuestionTable number contains many numbers in column num including duplicated ones.Can you write a SQL query to find the biggest number, which only appears once.+---+|num|+---+| 8 || 8

QuestionGiven a table customer holding customers information and the referee.+------+------+-----------+| id | name | referee_id|+------+------+-----------+| 1 | Will | NULL ||

QuestionTable point holds the x coordinate of some points on x-axis in a plane, which are all integers.Write a query to find the shortest distance between two points in these points.| x

题目很简单 看一下怎么用union完成 union的速度会更快些 There is a table World+-----------------+------------+------------+--------------+---------------+| name | continent | area | population |

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 | Departme

题目：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 |+----+------

题目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.+----+-------+| I

题目：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 |+-

我的答案select FirstName, LastName, City, Statefrom Person,Addresswhere Person.PersonId=Address.PersonId答案错误，因为题目中有提到regardless if there is an address for each of those people没有地址的信息也要显示出来 因此不能使

题目：Given a Weather table, write a SQL query to find all dates' Ids with higher temperature compared to its previous (yesterday's) dates.+---------+------------+------------------+| Id(INT)

QuestionA pupil Tim gets homework to identify whether three line segments could possibly form a triangle.However, this assignment is very heavy because there are hundreds of records to calcula

转自http://bookshadow.com/weblog/2017/05/05/leetcode-employee-bonus/题目描述：Select all employee's name and bonus whose bonus is Table:Employee+-------+--------+-----------+--------+| emp

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

QuestionA university uses 2 data tables, student and department, to store data about its students and the departments associated with each major.Write a query to print the respective departmen