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
1、FirstName与LastName在表1中,City与State在表2中
2、两个表共同的字段:PersonId
3、无论有无地址信息
4、联合查询
So show you my code:
# Write your MySQL query statement below
SELECT a.FirstName, a.LastName, b.City, b.State
FROM
(
SELECT FirstName, LastName, PersonId
FROM Person
) a
LEFT JOIN
(
SELECT City, State, PersonId
FROM Address
) b
ON a.PersonId=b.PersonId
Runtime: 356 ms