SQL

문제 Table: Employees +-------------+----------+ | Column Name | Type | +-------------+----------+ | employee_id | int | | name | varchar | | reports_to | int | | age | int | +-------------+----------+ employee_id is the column with unique values for this table. This table contains information about the employees and the id of the manager they report to. Some employees do not report to anyone (rep..

문제 Table: Followers +-------------+------+ | Column Name | Type | +-------------+------+ | user_id | int | | follower_id | int | +-------------+------+ (user_id, follower_id) is the primary key (combination of columns with unique values) for this table. This table contains the IDs of a user and a follower in a social media app where the follower follows the user. Write a solution that will, for ..

문제 Table: DailySales +-------------+---------+ | Column Name | Type | +-------------+---------+ | date_id | date | | make_name | varchar | | lead_id | int | | partner_id | int | +-------------+---------+ There is no primary key (column with unique values) for this table. It may contain duplicates. This table contains the date and the name of the product sold and the IDs of the lead and partner i..

문제 Table: Tweets +----------------+---------+ | Column Name | Type | +----------------+---------+ | tweet_id | int | | content | varchar | +----------------+---------+ tweet_id is the primary key (column with unique values) for this table. This table contains all the tweets in a social media app. Write a solution to find the IDs of the invalid tweets. The tweet is invalid if the number of charac..

문제 Table: Users +----------------+---------+ | Column Name | Type | +----------------+---------+ | user_id | int | | name | varchar | +----------------+---------+ user_id is the primary key (column with unique values) for this table. This table contains the ID and the name of the user. The name consists of only lowercase and uppercase characters. Write a solution to fix the names so that only th..

문제 Table: Activity +----------------+---------+ | Column Name | Type | +----------------+---------+ | machine_id | int | | process_id | int | | activity_type | enum | | timestamp | float | +----------------+---------+ The table shows the user activities for a factory website. (machine_id, process_id, activity_type) is the primary key (combination of columns with unique values) of this table. mac..

문제 Table: Users +-------------+---------+ | Column Name | Type | +-------------+---------+ | user_id | int | | user_name | varchar | +-------------+---------+ user_id is the primary key (column with unique values) for this table. Each row of this table contains the name and the id of a user. Table: Register +-------------+---------+ | Column Name | Type | +-------------+---------+ | contest_id |..

문제 Table: Users +--------------+---------+ | Column Name | Type | +--------------+---------+ | account | int | | name | varchar | +--------------+---------+ account is the primary key (column with unique values) for this table. Each row of this table contains the account number of each user in the bank. There will be no two users having the same name in the table. Table: Transactions +----------..

문제 Table: Visits +-------------+---------+ | Column Name | Type | +-------------+---------+ | visit_id | int | | customer_id | int | +-------------+---------+ visit_id is the column with unique values for this table. This table contains information about the customers who visited the mall. Table: Transactions +----------------+---------+ | Column Name | Type | +----------------+---------+ | tran..

문제 Table: Patients +--------------+---------+ | Column Name | Type | +--------------+---------+ | patient_id | int | | patient_name | varchar | | conditions | varchar | +--------------+---------+ patient_id is the primary key (column with unique values) for this table. 'conditions' contains 0 or more code separated by spaces. This table contains information of the patients in the hospital. Write..