Leetcode 175. Combine Two Tables

以左表为主合并两个表,使用left join... on ...语句.

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

# Write your MySQL query statement below
select Person.FirstName, Person.LastName,Address.City,Address.State
from Person
left join Address on Person.PersonId = Address.PersonId;

知识点:SQL JOIN语句总结