Leetcode-SQL习题

Leetcode-SQL

链接：https://leetcode-cn.com/problems/combine-two-tables/solution/zu-he-liang-ge-biao-by-leetcode/

习题来源：力扣（LeetCode）

目录

• Leetcode-SQL
  • 175-组合两个表-2021-01-09
  • 123
  • 456

175-组合两个表-2021-01-09

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表1：Person

列名	类型
PersonID	int
FirstName	varchar
LastName	varchar
*** ----------------------

PresonID 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

要求：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

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--我的答案
select
    FirstName,
    LastName,
    City,
    state
from
    (
        select
            PersonId,
            FirstName,
            LastName
        from
            Person
    ) a
    left join (
        select
            PersonId,
            City,
            State
        from
            Address
    ) b on a.PersonId = b.PersonId

--官方建议答案
select FirstName, LastName, City, State
from Person left join Address
on Person.PersonId = Address.PersonId

123

456