Description
SQL Schema
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
Solutions
1. Left Join
select p.FirstName, p.LastName, a.City, a.State
from Person p left join Address a on p.PersonId = a.PersonId;
-- 7/7 cases passed (478 ms)
-- Your runtime beats 72.49 % of mysql submissions
-- Your memory usage beats 100 % of mysql submissions (0B)
basic left join: 902ms.
SELECT FirstName, LastName, City, State
FROM Person
LEFT JOIN Address
ON Person.PersonId = Address.PersonId;
left join + using: 907ms
SELECT FirstName, LastName, City, State
FROM Person
LEFT JOIN Address
USING(PersonId);
natural left join: 940ms
SELECT FirstName, LastName, City, State
FROM Person
NATURAL LEFT JOIN Address;
left join is the fastest compare to the two others.