𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄𝗲𝗿: You have 2 minutes to solve this SQL query.

Find the second highest salary in each department from the employees table, excluding any department with fewer than 2 employees.

𝗠𝗲: Challenge accepted!

SELECT 
    department, 
    MAX(salary) AS second_highest_salary
FROM (
    SELECT 
        department, 
        salary,
        ROW_NUMBER() OVER (PARTITION BY department ORDER BY salary DESC) as rn
    FROM employees
) ranked
WHERE rn = 2
GROUP BY department;

I used a subquery with ROW_NUMBER() window function partitioned by department to rank salaries in descending order within each department. The outer query then filters for rank 2 (second highest) and groups to get distinct departments. This demonstrates mastery of window functions, which are essential for advanced analytics and ranking problems.

𝗧𝗶𝗽 𝗳𝗼𝗿 𝗦𝗤𝗟 𝗝𝗼𝗯 𝗦𝗲𝗲𝗸𝗲𝗿𝘀:
Window functions like ROW_NUMBER(), RANK(), and DENSE_RANK() unlock complex ranking and analytics—practice them daily to ace behavioral and technical rounds!

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