183. Customers Who Never Order 原题链接:https://leetcode.com/problems/customers-who-never-order/description/ 做完这道题目我才发现,我跟不就不懂 in, exists, not in, not exists,exists 用都不会用:...183. Customers Who Never Order https://leetcode.com/problems/customers-who-never-order/...
假设一个网站包含两个表,Customers表和Orders表。编写一个SQL语句找出所有从不订购任何东西的客户。 创建表和数据: CreatetableIfNotExistsCustomers (Idint, Namevarchar(255));CreatetableIfNotExistsOrders (Idint,CustomerIdint);TruncatetableCustomers;insertintoCustomers (Id, Name)values('1','Joe');insertint...
使用的方法是表customers和表orders左连接,并且条件是customerId为空的客户: 1 2 3 SELECTNAMEasCustomersFROMcustomersasa LEFTJOINordersasbona.Id = b.CustomerId WHEREb.CustomerIdisNULL; 解法二: 使用的方法是使用not in : 1 2 3 SELECTNameasCustmoersFROMcustomersasa WHEREa.Idnotin (SELECTb.CustomerId...
Can you solve this real interview question? Customers Who Never Order - Table: Customers +---+---+ | Column Name | Type | +---+---+ | id | int | | name | varchar | +---+---+ id is t
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. 假设一个网站包含两个表: Customers和Orders。写出一个SQL查询语句找出所有没有任何订单的顾客。
https://leetcode-cn.com/problems/customers-who-never-order/ 📕解题思路 根据题目,我们先看题目要求我们查什么,要查出从不订购任何东西的顾客。根据这一点我们可以从Orders订单表中得知CustomerId为1和3的是订购过东西的顾客,而2和4则没有订购过任何东西。再从Customers顾客表中查id2与id4对应的顾客名字就查...
Customers Who Never Order 前言 这篇文章主要帮助大家开启对 SQL 的了解与学习,总结了 LeetCode 中的 Database 中 SQL(简单)里面代表性较高且值得去反复做的 47 道题,希望能对大家入门 SQL 有所帮助! Now, Let's get started! 1. Actors and Directors Who Cooperated At Least Three Times 注意到,这里的...
日 一 练 ” Day 1365 DS Interview Question Why is Manhattan distance not used in kNN machine learning algorithm to calculate the distance between nearest neighbours? BA Interview Question Customers Who Never Order Suppose that a website contains two tables, the Customers table and the Orders table...
13. Customers Who Never Order 这个题比较简单,依旧考察大家对 join 和缺失值的运用,首先使用left join连接两表,在使用where设定题中所给的条件即可。 正确答案如下: select name, bonus from Employee left join Bonus using (empId) where bonus < 1000 or bonus is null # 要注意缺失值也要体现出来,如果没...
Customers Who Never Order 【题目】 Suppose that a website contains two tables, theCustomerstable and theOrderstable. Write a SQL query to find all customers who never order anything. Table:Customers. +---+---+ | Id | Name | +---+---+ | 1 | Joe | | 2 | Henry | | 3 | Sam...