175. 组合两个表

Posted 2020-11-07 如有一味绝境，非历十方生死

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

AC：

1 # Write your mysql query statement below
2 select Person.FirstName, Person.LastName, Address.City, Address.State
3 from Person 
4 left join Address
5 on Person.PersonId=Address.PersonId

知识点：LEFT JOIN