What query calculates the cumulative sum of sales within each category?, SELECT category_id, sales_amount, SUM(sales_amount) OVER (PARTITION BY category_id ORDER BY order_date) AS cumulative_sales FROM sales;, SELECT SUM(sales_amount) FROM sales GROUP BY category_id;, SELECT sales_amount FROM sales WHERE category_id IS NOT NULL;, SELECT SUM(sales_amount) FROM sales;, How do you retrieve the difference in salary between each employee and their department's average?, SELECT * FROM employees WHERE salary = AVG(salary);, SELECT DISTINCT department_id, salary FROM employees;, SELECT salary FROM employees ORDER BY salary;, SELECT employee_id, salary, salary - AVG(salary) OVER (PARTITION BY department_iAS salary_diff FROM employees;, How do you find all customers who have placed at least three orders?, SELECT customer_id FROM orders GROUP BY customer_id HAVING COUNT(order_i>= 3;, SELECT DISTINCT customer_id FROM orders WHERE COUNT(order_i>= 3;, SELECT customer_id FROM orders WHERE order_id >= 3;, SELECT * FROM customers WHERE orders >= 3;, What query finds customers who have never placed an order?, SELECT customer_id FROM customers WHERE orders = 0;, SELECT * FROM customers WHERE customer_id NOT IN (SELECT customer_id FROM orders);, SELECT DISTINCT customer_id FROM orders;, SELECT customer_id FROM orders WHERE order_id IS NULL;, How do you find the median salary from an employees table?, SELECT AVG(salary) FROM employees;, SELECT salary FROM ( SELECT salary, ROW_NUMBER() OVER (ORDER BY salary) AS row_num, COUNT(*) OVER() AS total_rows FROM employees) ranked WHERE row_num = total_rows / 2 OR row_num = (total_rows / 2) + 1;, SELECT MEDIAN(salary) FROM employees;, SELECT salary FROM employees WHERE salary > 0;, How do you retrieve the last three orders placed by each customer?, SELECT employee_id FROM employees WHERE salary = salary;, SELECT DISTINCT employee_id FROM employees;, SELECT employee_id FROM employees ORDER BY salary;, SELECT e1.* FROM employees e1 JOIN employees e2 ON e1.department_id = e2.department_id AND e1.salary = e2.salary AND e1.employee_id <> e2.employee_id;, How do you find employees who have the same salary as another employee in the same department?, SELECT DISTINCT employee_id FROM employees;, SELECT e1.* FROM employees e1 JOIN employees e2 ON e1.department_id = e2.department_id AND e1.salary = e2.salary AND e1.employee_id <> e2.employee_id;, SELECT employee_id FROM employees WHERE salary = salary;, SELECT employee_id FROM employees ORDER BY salary;, What query retrieves employees who have a direct manager?, SELECT e1.employee_id, e1.name, e2.name AS manager_name FROM employees e1 JOIN employees e2 ON e1.manager_id = e2.employee_id;, SELECT * FROM employees WHERE manager_id IS NOT NULL;, SELECT DISTINCT employee_id FROM employees;, SELECT employee_id FROM employees ORDER BY manager_id;, How do you find the percentage contribution of each product to total sales?, SELECT product_id, SUM(sales_amount) AS product_sales, SUM(sales_amount) * 100.0 / SUM(SUM(sales_amount)) OVER () AS percentage_contribution FROM sales GROUP BY product_id;, SELECT DISTINCT product_id, SUM(sales_amount) FROM sales;, SELECT product_id FROM sales ORDER BY sales_amount;, SELECT * FROM sales WHERE sales_amount > 0;, How do you calculate the year-over-year growth in sales?, SELECT DISTINCT year, sales_amount FROM sales;, SELECT year, sales_amount, sales_amount - LAG(sales_amount) OVER (ORDER BY year) AS yoy_growth FROM sales;, SELECT year, SUM(sales_amount) FROM sales GROUP BY year;, SELECT year FROM sales ORDER BY sales_amount;.

SQL Query-Based Quiz 3

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