练习地址:https://leetcode-cn.com/problems/combine-two-tables/
表1: Person +-------------+---------+ | 列名 | 类型 | +-------------+---------+ | PersonId | int | | FirstName | varchar | | LastName | varchar | +-------------+---------+ PersonId 是上表主键 表2: Address +-------------+---------+ | 列名 | 类型 | +-------------+---------+ | AddressId | int | | PersonId | int | | City | varchar | | State | varchar | +-------------+---------+ AddressId 是上表主键 编写一个 SQL 查询,满足条件:无论 person 是否有地址信息,都需要基于上述两表提供 person 的以下信息: FirstName, LastName, City, State
答案:
select a.FirstName,a.LastName,b.City,b.State from Person a left join Address b on a.PersonId =b.PersonId
原文地址:https://www.cnblogs.com/8013-cmf/p/12411061.html
时间: 2024-11-07 16:51:58