[MySQL] LeetCode : Combine Two Tables Solution

 

 

https://leetcode.com/problems/combine-two-tables/submissions/

Combine Two Tables - LeetCode

Table: Person

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| personId    | int     |
| lastName    | varchar |
| firstName   | varchar |
+-------------+---------+
personId is the primary key column for this table.
This table contains information about the ID of some persons and their first and last names.

 

Table: Address

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| addressId   | int     |
| personId    | int     |
| city        | varchar |
| state       | varchar |
+-------------+---------+
addressId is the primary key column for this table.
Each row of this table contains information about the city and state of one person with ID = PersonId.

 

Write an SQL query to report the first name, last name, city, and state of each person in the Person table. If the address of a personId is not present in the Address table, report null instead.

Return the result table in any order.

 

 

1. 코드 구현 

# left join 사용 
SELECT p.firstName, p.lastName, a.city, a.state
FROM Person p 
LEFT JOIN Address a ON p.personId = a.personId;