LeetCode：175. Combine Two Tables

题目：
Table: Person

+————-+———+
| Column Name | Type |
+————-+———+
| PersonId | int |
| FirstName | varchar |
| LastName | varchar |
+————-+———+
PersonId is the primary key column for this table.
Table: Address

+————-+———+
| Column Name | Type |
+————-+———+
| AddressId | int |
| PersonId | int |
| City | varchar |
| State | varchar |
+————-+———+
AddressId is the primary key column for this table.

Write a SQL query for a report that provides the following information for each person in the Person table, regardless if there is an address for each of those people:

FirstName, LastName, City, State

Answer：
思路：因each person and regardless address，采用LEFT JOIN

# Write your MySQL query statement below
SELECT
    FirstName,
    LastName,
    City,
    State 
FROM
    person
    LEFT JOIN address ON person.PersonId = address.PersonId

附SQL各种JOIN关系图：

还有下面这个图：