LeetCode

Data Analysis/TIL

[LeetCode] 175. Combine Two Tables_a, b 테이블 조인하고 b 테이블에 없는 정보는 Null값으로 나오게 하라 = 해당 정보가 없어도 보이게 하라

문제 +-------------+---------+ | 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 | +-------------+-----..

Data Analysis/TIL

[LeetCode] 182. Duplicate Emails_중복 건을 뽑고 싶을 때

문제 +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | email | varchar | +-------------+---------+ id is the primary key column for this table. Each row of this table contains an email. The emails will not contain uppercase letters. Write an SQL query to report all the duplicate emails. Return the result table in any order. The query result format is in the ..

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