SQL/LeetCode

문제 Table: Activity +--------------+---------+ | Column Name | Type | +--------------+---------+ | player_id | int | | device_id | int | | event_date | date | | games_played | int | +--------------+---------+ (player_id, event_date) is the primary key (combination of columns with unique values) of this table. This table shows the activity of players of some games. Each row is a record of a player..

문제 Table: Person +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | email | varchar | +-------------+---------+ id is the primary key (column with unique values) for this table. Each row of this table contains an email. The emails will not contain uppercase letters. Write a solution to report all the duplicate emails. Note that it's guaranteed that the emai..

문제 Table: Employee +-------------+------+ | Column Name | Type | +-------------+------+ | id | int | | salary | int | +-------------+------+ id is the primary key (column with unique values) for this table. Each row of this table contains information about the salary of an employee. Write a solution to find the second highest salary from the Employee table. If there is no second highest salary, ..

문제 Table: Person +-------------+---------+ | Column Name | Type | +-------------+---------+ | personId | int | | lastName | varchar | | firstName | varchar | +-------------+---------+ personId is the primary key (column with unique values) for this table. This table contains information about the ID of some persons and their first and last names. Table: Address +-------------+---------+ | Column..

문제 Table: Employee +--------------+---------+ | Column Name | Type | +--------------+---------+ | id | int | | name | varchar | | salary | int | | departmentId | int | +--------------+---------+ id is the primary key (column with unique values) for this table. departmentId is a foreign key (reference column) of the ID from the Department table. Each row of this table indicates the ID, name, and ..

문제 Table: Logs +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | num | varchar | +-------------+---------+ In SQL, id is the primary key for this table. id is an autoincrement column. Find all numbers that appear at least three times consecutively. Return the result table in any order. The result format is in the following example. https://leetcode.com/pro..

문제 Table: Employee +--------------+---------+ | Column Name | Type | +--------------+---------+ | id | int | | name | varchar | | salary | int | | departmentId | int | +--------------+---------+ id is the primary key (column with unique values) for this table. departmentId is a foreign key (reference columns) of the ID from the Department table. Each row of this table indicates the ID, name, and..

문제 Table: Person +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | email | varchar | +-------------+---------+ id is the primary key (column with unique values) for this table. Each row of this table contains an email. The emails will not contain uppercase letters. Write a solution to delete all duplicate emails, keeping only one unique email with the smal..

문제 Table: Salary +-------------+----------+ | Column Name | Type | +-------------+----------+ | id | int | | name | varchar | | sex | ENUM | | salary | int | +-------------+----------+ id is the primary key (column with unique values) for this table. The sex column is ENUM (category) value of type ('m', 'f'). The table contains information about an employee. Write a solution to swap all 'f' and ..

문제 Table: Weather +---------------+---------+ | Column Name | Type | +---------------+---------+ | id | int | | recordDate | date | | temperature | int | +---------------+---------+ id is the column with unique values for this table. This table contains information about the temperature on a certain day. Write a solution to find all dates' Id with higher temperatures compared to its previous dat..