30 SQL Interview Questions For Business Analyst in 2025

SQL is an essential skill for Business Analysts which helps them to retrieve and analyze data from databases. It enables them to generate reports, find trends, and support decision-making. SQL enables analysts to extract, manipulate and analyze data from relational databases that help organizations gain valuable insights.

Whether we're preparing for a job interview or looking to enhance our SQL skills, this article presents 30 essential SQL interview questions customized for Business Analysts in 2025. Covering beginner to advanced levels, these questions will help you to build a strong foundation and confidently solve SQL-related challenges in a business environment.

Beginner-Level SQL Interview Questions

Beginner-level SQL interview questions focus on the fundamentals of SQL which is essential for Business Analysts. These questions cover basic data retrieval (SELECT statements), filtering data using WHERE, sorting results with ORDER BY and aggregating data using GROUP BY.

Additionally, they include joins, subqueries and simple data modifications like UPDATE and DELETE. Understanding these concepts helps analysts extract, manipulate, and analyze data efficiently for business insights.

1. What is SQL and why is it important for Business Analysts?

SQL (Structured Query Language) is used to interact with relational databases. Business Analysts use SQL to extract insights from data, generate reports, and support data-driven decision-making. It allows them to retrieve specific data points, filter datasets and perform aggregations, making it a crucial tool for analytical roles.

2. Explain the basic syntax of a SELECT statement.

The SELECT statement is used to fetch data from a table. The syntax follows:

SELECT column1, column2 FROM table_name;

Example:

SELECT name, age FROM employees;

Explanation: This query retrieves the names and ages of all employees from the employees table.

3. How do you retrieve all records from a table?

To retrieve all records from a table, use the SELECT * statement, which fetches all columns and rows from the specified table

SELECT * FROM Customers;

Explanation:

• The SELECT * statement retrieves all columns and all rows from the Customers table.
• It is useful when you need a complete dataset, but it's recommended to select specific columns when dealing with large tables for better performance..

4. What is the WHERE clause used for?

The WHERE clause filters records based on specified conditions, retrieving only relevant rows before aggregation or grouping in a SQL query.

SELECT product_name, price FROM products WHERE price > 50;

It retrieves products where the price is greater than 50.

5. What is the purpose of the GROUP BY clause?

GROUP BY is used to group rows that have the same values in specified columns. It is typically used with aggregate functions such as COUNT, SUM, AVG, etc.

SELECT department, AVG(salary)  
FROM employees  
GROUP BY department;

Explanation:

• This query groups employees by department.
• It then calculates the average salary for each department using the AVG(salary) function.
• The result shows one row per department with the corresponding average salary. This is useful for analyzing data at a category level, such as total sales per region or number of employees per department.

6. How is HAVING different from WHERE?

• WHERE: It filters individual records before the `GROUP BY` operation, ensuring only relevant rows are selected based on specified conditions before aggregation occurs.
• HAVING It filters aggregated data after the `GROUP BY` operation, applying conditions on aggregate functions like SUM(), AVG(), or COUNT() to refine grouped results..

SELECT department, AVG(salary) 
FROM employees 
GROUP BY department 
HAVING AVG(salary) > 50000;

This retrieves departments where the average salary exceeds 50,000.

7. How do you sort query results in descending order?

SELECT product_name, price 
FROM products 
ORDER BY price DESC;

Explanation:

• The ORDER BY clause sorts the query results based on a specified column.
• DESC sorts the values in descending order (highest to lowest).

In this example, products are sorted by price from highest to lowest.

8. What is an INNER JOIN?

An INNER JOIN combines records from two tables based on a matching column. It returns only rows where there is a match in both tables

SELECT employees.name, departments.dept_name  
FROM employees  
INNER JOIN departments ON employees.dept_id = departments.dept_id;

This retrieves employee names along with their department names.

9. What is a subquery?

A subquery is a query nested inside another query. It is used to retrieve data that will be used as a condition in the main query.

SELECT product_name FROM products WHERE price > (SELECT AVG(price) FROM products);

Explanation:

• The inner query (SELECT AVG(price) FROM products) calculates the average price of all products.
• The outer query retrieves product names where the price is greater than the average price.
• Subqueries help perform complex filtering, calculations, and comparisons within a single SQL query.

10. How do you update records in a table?

To update records in a table, use the UPDATE statement with the SET clause to modify specific column values and the WHERE clause to specify which rows to update.

UPDATE customers  
SET city = 'New York'  
WHERE customer_id = 123;

Explanation:

• The UPDATE statement modifies existing records in a table.
• The SET clause assigns new values to one or more columns.
• The WHERE clause ensures that only the intended record(s) are updated.

In this example, the city of the customer with customer_id = 123 is changed to 'New York'.

11. What is the DISTINCT keyword used for?

The DISTINCT keyword removes duplicate values from the result set, ensuring only unique records are retrieved from a specific column. It helps in finding unique entries in a dataset.

SELECT DISTINCT department FROM employees;

Explanation:

• This query selects all unique department names from the employees table.
• If multiple employees belong to the same department, it appears only once in the result.
• The DISTINCT keyword is useful for identifying unique categories, filtering duplicate records, and ensuring cleaner data retrieval.

12. How do you count the number of rows in a table?

SELECT COUNT(*) FROM table_name;

This returns the total number of rows in the table.

Intermediate-Level SQL Interview Questions

Intermediate-level SQL interview questions delve deeper into data manipulation and complex queries. They cover concepts like self-joins, subqueries and CASE statements to handle conditional logic.

Additionally, they focus on data aggregation, extracting specific date parts and fetching ranked results (e.g., second-highest salary). These topics help Business Analysts perform advanced data analysis, categorize records and optimize queries for better performance.

16. What is a self-join?

A self-join joins a table with itself, commonly used for hierarchical relationships like employees and managers. It matches rows within the same table using aliases to differentiate them.

SELECT e1.name, e2.name 
FROM employees e1 JOIN employees e2 
ON e1.manager_id = e2.employee_id;

This retrieves employees and their corresponding managers.

18. How do you extract the year from a date column?

SELECT YEAR(order_date) FROM orders;

This extracts the year from the order_date column.

19. What is a CASE statement?

A CASE statement allows conditional logic in SQL queries, similar to an IF-ELSE structure. It is used to categorize, transform, or filter data based on specified conditions

SELECT order_id,  
    CASE  
        WHEN amount > 1000 THEN 'High'  
        WHEN amount > 500 THEN 'Medium'  
        ELSE 'Low'  
    END AS order_category  
FROM orders;

Explanation:

• If amount is greater than 1000, the order_category column is labeled as 'High'.
• If amount is between 501 and 1000, it is labeled as 'Medium'.
• If amount is 500 or less, it is labeled as 'Low'.
• This helps classify orders based on their total amount.

22. How do you fetch the second-highest salary?

To fetch the second-highest salary, we need to find the maximum salary that is less than the highest salary. This can be done using a subquery with the MAX() function.

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

Explanation:

• The inner query SELECT MAX(salary) FROM employees retrieves the highest salary.
• The outer query finds the maximum salary that is less than the highest salary, effectively returning the second-highest salary:

23. What is a CROSS JOIN?

A CROSS JOIN returns the Cartesian product of two tables.

SELECT * FROM products CROSS JOIN categories;

This returns all possible combinations of products and categories.

Advanced-Level SQL Interview Questions

Advanced-level SQL interview questions focus on complex query optimization, recursive queries, window functions, and stored procedures. These concepts help Business Analysts handle hierarchical data, improve query efficiency, and create reusable SQL logic.

Topics like Common Table Expressions (CTEs), CROSS JOINs and indexing strategies enable better performance and scalability in large databases. Mastering these topics allows analysts to work with big data, optimize reporting and streamline decision-making processes.

26. What are window functions in SQL?

Window functions perform calculations across a subset of rows related to the current row.

SELECT name, salary, RANK() 
OVER (ORDER BY salary DESC) AS salary_rank 
FROM employees;

This ranks employees based on their salary.

27. What is the WITH clause used for?

The WITH clause, also known as a Common Table Expression (CTE), creates a temporary result set that can be referenced within the main query. It improves query readability and reusability.

WITH SalesData AS (  
    SELECT customer_id, SUM(amount) AS total_spent  
    FROM orders  
    GROUP BY customer_id  
)  
SELECT * FROM SalesData WHERE total_spent > 500;

Explanation:

• The WITH clause defines a temporary table (SalesData) that calculates the total spending per customer.
• The main query retrieves only customers who have spent more than 500.

Using WITH simplifies complex queries by breaking them into smaller, manageable parts

28. What is a recursive query?

A recursive query is a query that calls itself repeatedly to retrieve hierarchical or tree-structured data, such as organizational charts or category hierarchies. It is commonly used with Common Table Expressions (CTEs).

WITH RECURSIVE EmployeeHierarchy AS (  
    SELECT employee_id, name, manager_id  
    FROM employees  
    WHERE manager_id IS NULL  -- Get the top-level manager  
    UNION ALL  
    SELECT e.employee_id, e.name, e.manager_id  
    FROM employees e  
    JOIN EmployeeHierarchy eh ON e.manager_id = eh.employee_id  
)  
SELECT * FROM EmployeeHierarchy;

Explanation:

• The base query retrieves the top-level manager (manager_id IS NULL).
• The recursive part joins employees to their managers, building the hierarchy step by step.
• The query runs until all employee-manager relationships are retrieved.

Recursive queries are useful for fetching data with parent-child relationships, such as company structures, bill of materials, and directory trees

29. What is a stored procedure?

A stored procedure is a precompiled SQL block that executes a set of SQL statements. It improves performance, reduces redundancy, and enhances security by encapsulating business logic inside the database.

CREATE PROCEDURE GetEmployeeData()  
AS  
BEGIN  
    SELECT * FROM employees;  
END;

Explanation:

The CREATE PROCEDURE statement defines a stored procedure named GetEmployeeData().

• Inside the procedure, the SELECT * FROM employees; statement retrieves all employee records.
• Stored procedures are executed using EXEC GetEmployeeData();.
• Stored procedures reduce network traffic, enhance security by limiting direct table access, and improve performance through query optimization

30. How do you optimize a SQL query?

Optimizing SQL queries involves:

• Using indexes to speed up lookups
• Avoiding SELECT * to fetch only necessary columns
• Using JOINs efficiently
• Using appropriate data types
• Limiting results to reduce query execution time

Conclusion

Overall, SQL remains a important tool for Business Analysts which allowing them to retrieve and analyze data efficiently. By mastering fundamental concepts such as SELECT queries, JOIN operations, aggregation and optimization techniques.

Business Analysts can drive data-informed decisions and improve business performance. As data continues to play a significant role in shaping strategies, having strong SQL skills will give professionals a competitive edge in 2025 and beyond. Preparing for these interview questions will not only boost confidence but also ensure success in handling real-world business data challenges.