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  • [SQL]LeetCode175. 组合两个表 | Combine Two Tables

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    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

    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

    186ms
    1 # Write your MySQL query statement below
    2 SELECT Person.FirstName,Person.LastName,Address.City,Address.State
    3 From Person left join Address
    4 on Person.PersonId=Address.PersonId

    190ms

    1 SELECT Person.FirstName, Person.LastName, Address.City, Address.State FROM Person LEFT JOIN Address USING(PersonId);

    192ms

    1 SELECT Person.FirstName, Person.LastName, Address.City, Address.State FROM Person NATURAL LEFT JOIN Address;
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  • 原文地址:https://www.cnblogs.com/strengthen/p/9720770.html
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