SQL queries interview questions

🟢 LEVEL 1 — Basic SELECT

• Show all employees.
• Show only employee names and salary.
• Show employees with salary > 60000.
• Show employees hired after 2021.
• Show employees who work in department 1.
• Show unique department IDs from employees.
• Show employees sorted by salary descending.
• Show top 3 highest paid employees.
• Count total employees.
• Count female employees.

🟡 LEVEL 2 — WHERE + GROUP BY

• Count employees in each department.
• Average salary per department.
• Max salary in company.
• Min salary in company.
• Total salary paid by company.
• Count employees hired after 2020.
• Show departments having more than 2 employees.
• Show department with highest avg salary.
• Count employees by gender.
• Show employees whose name starts with 'S'.

🟠 LEVEL 3 — JOINS (Important)

• Show employee name with department name.
• Show employees working in Engineering department.
• Show employee + department + location.
• Show all employees and their projects (via department).
• Count employees in each department with department name.
• Show employees who belong to Pune location.
• Show employees with no department (LEFT JOIN case).
• Show department with total salary of employees.
• Show highest paid employee in each department.
• Show departments with no employees.

🔵 LEVEL 4 — Salary & History

• Show employees who got increment.
• Show old salary vs new salary.
• Highest increment given to which employee?
• Count total increments.
• Employees whose salary increased >5000.
• Latest increment date.
• Show employee name with increment details.
• Total increment amount company paid.
• Employees who never got increment.
• First employee who got increment.

🟣 LEVEL 5 — Attendance

• Show all absent employees.
• Count present employees.
• Count absent employees.
• Show attendance for employee Swapnil.
• Employees working from home.
• Count attendance per employee.
• Employee with most absences.
• Show attendance with employee name.
• Count attendance per day.
• Employees absent on 2026-02-01.

🔴 LEVEL 6 — Advanced (Interview level)

• 2nd highest salary.
• 3rd highest salary.
• Employees earning above company average.
• Department with highest total salary.
• Employee with highest salary in each department.
• Rank employees by salary.
• Show duplicate salaries.
• Employees who earn more than their manager (assume self compare).
• Running total of salaries.
• Salary difference between highest and lowest.

🏆 SUPER CHALLENGE (Real interview)

• Top 3 salaries per department.
• Department where avg salary > company avg.
• Employees hired in last 2 years.
• Salary ranking within department.
• Department with no projects.
• Project count per department.
• Employees working on same dept as Swapnil.
• Highest salary in Pune location.
• Attendance percentage per employee.
• Create view for employee + dept + salary.