Dev.D

*Problem Write a solution to calculate the number of unique subjects each teacher teaches in the university.Return the result table in any order. *ExplanationTeacher 1: - They teach subject 2 in departments 3 and 4. - They teach subject 3 in department 3.Teacher 2: - They teach subject 1 in department 1. - They teach subject 2 in department 1. - They teach subject 3 in department 1. - They..

* ProblemWrite a solution to report the fraction of players that logged in again on the day after the day they first logged in, rounded to 2 decimal places. In other words, you need to count the number of players that logged in for at least two consecutive days starting from their first login date, then divide that number by the total number of players. * ExplanationOnly the player with id 1 log..

* ProblemIf the customer's preferred delivery date is the same as the order date, then the order is called immediate; otherwise, it is called scheduled.The first order of a customer is the order with the earliest order date that the customer made. It is guaranteed that a customer has precisely one first order.Write a solution to find the percentage of immediate orders in the first orders of all ..

* ProbelmWrite an SQL query to find for each month and country, the number of transactions and their total amount, the number of approved transactions and their total amount.Return the result table in any order. * Solution# Write your MySQL query statement below Select DATE_FORMAT(trans_date, '%Y-%m') AS month,             country,             COUNT(*) AS trans_count,             sum(state='appr..

* ProblemWe define query quality as:The average of the ratio between query rating and its position.We also define poor query percentage as:The percentage of all queries with rating less than 3.Write a solution to find each query_name, the quality and poor_query_percentage.Both quality and poor_query_percentage should be rounded to 2 decimal places.Return the result table in any order.The result ..

* Problem Write a solution to find the percentage of the users registered in each contest rounded to two decimals.Return the result table ordered by percentage in descending order. In case of a tie, order it by contest_id in ascending order. Explanation: All the users registered in contests 208, 209, and 210. The percentage is 100% and we sort them in the answer table by contest_id in ascending ..

* ProblemWrite an SQL query that reports the average experience years of all the employees for each project, rounded to 2 digits.Return the result table in any ordeExplanation: The average experience years for the first project is (3 + 2 + 1) / 3 = 2.00 and for the second project is (3 + 2) / 2 = 2.50 * Solution # Write your MySQL query statement below select  a.project_id project_id,           ..

* ProblemWrite a solution to find the average selling price for each product. average_price should be rounded to 2 decimal places. If a product does not have any sold units, its average selling price is assumed to be 0.Return the result table in any order.Explanation: Average selling price = Total Price of Product / Number of products sold.Average selling price for product 1 = ((100 * 5) + (15 *..