使用左连接，以左表为基础，若右表中没有对应数据，则显示为NULL
难度简单1047
SQL架构
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
# Write your MySQL query statement below
select FirstName, LastName, City, State
from Person LEFT join Address on Person.PersonId=Address.PersonId知识拓展
内连接
SELECT O.ID,O.ORDER_NUMBER,C.ID,C.NAME
FROM CUSTOMERS C INNER JOIN ORDERS O ON C.ID=O.CUSTOMER_ID;
左连接
LEFT JOIN或LEFT OUTER JOIN
右连接
RIGHT JOIN 或 RIGHT OUTER JOIN