Interview Q&A / SQL & DBMS
SQL & DBMS interview questions
Joins, keys, normalisation, indexes and transactions for placement and backend interviews.
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- Write an SQL query to find the second highest salary.
Find the highest salary that is less than the maximum, with SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees). For the Nth highest, use DENSE_RANK() so that duplicate salaries share a rank, or ORDER BY DISTINCT salary with LIMIT and OFFSET.
BeginnerIn-depthCoding3 min read - Write a query to list departments that have more than 5 employees.
Group by department and filter groups with HAVING COUNT(*) > 5. WHERE cannot be used because the count exists only after grouping.
BeginnerQuick answerCoding1 min read