Jerry's Study Station Jerry's Study Station

난이도 : Medium Table: Employees +--------------+------+ | Column Name | Type | +--------------+------+ | employee_id | int | | needed_hours | int | +--------------+------+ employee_id is the primary key for this table. Each row contains the id of an employee and the minimum number of hours needed for them to work to get their salary. Table: Logs +-------------+----------+ | Column Name | Type | +-..

난이도 : Medium Table: CoffeeShop +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | drink | varchar | +-------------+---------+ id is the primary key for this table. Each row in this table shows the order id and the name of the drink ordered. Some drink rows are nulls. Write an SQL query to replace the null values of drink with the name of the drink of the pr..

난이도 : Medium Table: Salesperson +----------------+---------+ | Column Name | Type | +----------------+---------+ | salesperson_id | int | | name | varchar | +----------------+---------+ salesperson_id is the primary key for this table. Each row in this table shows the ID of a salesperson. Table: Customer +----------------+------+ | Column Name | Type | +----------------+------+ | customer_id | i..

난이도 : Medium Table: Students +---------------+------+ | Column Name | Type | +---------------+------+ | student_id | int | | department_id | int | | mark | int | +---------------+------+ student_id is the primary key of this table. Each row of this table indicates a student's ID, the ID of the department in which the student enrolled, and their mark in the exam. Write an SQL query that reports t..

난이도 : Medium Table: Sales +-------------+-------+ | Column Name | Type | +-------------+-------+ | sale_id | int | | product_id | int | | user_id | int | | quantity | int | +-------------+-------+ sale_id is the primary key of this table. product_id is a foreign key to Product table. Each row of this table shows the ID of the product and the quantity purchased by a user. Table: Product +--------..

난이도 : Medium Table: Weather +-------------+------+ | Column Name | Type | +-------------+------+ | city_id | int | | day | date | | degree | int | +-------------+------+ (city_id, day) is the primary key for this table. Each row in this table contains the degree of the weather of a city on a certain day. All the degrees are recorded in the year 2022. Write an SQL query to report the day that has..

난이도 : Medium Table: Genders +-------------+---------+ | Column Name | Type | +-------------+---------+ | user_id | int | | gender | varchar | +-------------+---------+ user_id is the primary key for this table. gender is ENUM of type 'female', 'male', or 'other'. Each row in this table contains the ID of a user and their gender. The table has an equal number of 'female', 'male', and 'other'. Wri..

난이도 : Hard Table: Tasks +----------------+---------+ | Column Name | Type | +----------------+---------+ | task_id | int | | subtasks_count | int | +----------------+---------+ task_id is the primary key for this table. Each row in this table indicates that task_id was divided into subtasks_count subtasks labeled from 1 to subtasks_count. It is guaranteed that 2