Top 10 Most Asked SQL Queries in Data Analyst Interviews (With Real-World Examples)

SQL is the most crucial skill for data analysts. Whether you’re applying for a junior or senior role, SQL queries are guaranteed to appear in your interview. In this guide, you’ll learn the top 10 SQL queries most frequently asked in data analyst interviews—with clear examples and explanations.

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1. Select Top N Records

SELECT * FROM sales
ORDER BY total_amount DESC
LIMIT 5;

Explanation: Fetches top 5 highest sales. Use TOP 5 in SQL Server or ROWNUM <= 5 in Oracle.

2. Find Duplicate Records

SELECT customer_id, COUNT(*)
FROM orders
GROUP BY customer_id
HAVING COUNT(*) > 1;

Explanation: Identifies customers who placed multiple orders.

3. SQL Joins Interview Scenario

SELECT e.name, d.department_name
FROM employees e
INNER JOIN departments d ON e.department_id = d.id;

Explanation: Combines employee and department data using INNER JOIN.

4. Get Second Highest Salary

SELECT MAX(salary)
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);

Explanation: Uses subquery to find the second highest salary.

5. Count Records Grouped by a Column

SELECT department, COUNT(*) AS total_employees
FROM employees
GROUP BY department;

Explanation: Shows total employees in each department.

6. SQL Date Filtering

SELECT * 
FROM transactions
WHERE transaction_date BETWEEN '2024-01-01' AND '2024-12-31';

Explanation: Filters data between two dates using BETWEEN.

7. NULL Handling in WHERE Clause

SELECT * 
FROM customers
WHERE email IS NULL;

Explanation: Finds records where email is missing. Use IS NULL instead of = NULL.

8. Subquery in WHERE Clause

SELECT name
FROM employees
WHERE department_id IN (
  SELECT id FROM departments WHERE location = 'New York'
);

Explanation: Filters employees working in New York based on department.

9. Window Function for Running Total

SELECT customer_id, order_date,
       SUM(amount) OVER (PARTITION BY customer_id ORDER BY order_date) AS running_total
FROM orders;

Explanation: Uses SUM OVER() for cumulative total per customer.

10. Convert Rows to Columns (Pivot)

SELECT department,
       SUM(CASE WHEN gender = 'Male' THEN 1 ELSE 0 END) AS Male,
       SUM(CASE WHEN gender = 'Female' THEN 1 ELSE 0 END) AS Female
FROM employees
GROUP BY department;

Explanation: Pivots gender data per department without using built-in PIVOT function.

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🧠 Interview Tips

Interviewers not only expect correct syntax—they want you to think in terms of performance, data quality, and business insight. Practice these queries on real data to master them before your next interview!

📌 FAQs

Q1: What SQL should I learn for data analyst interviews?: A: Learn SELECT, JOIN, GROUP BY, ORDER BY, subqueries, and window functions.
Q2: Which SQL database is used most in interviews?: A: MySQL, PostgreSQL, SQL Server, and Oracle are commonly used—SQL syntax is largely the same across them.
Q3: What are tricky SQL questions?: A: Finding nth highest value, pivot queries, NULL handling, and running totals using window functions are common tricky questions.

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