Is SQL Still Worth Learning in 2025?   

Absolutely.   

In this world driven by data, SQL (Structured Query Language) continues to be the foundational element behind data manipulation, data analysis, and even backend third-party DBMS design.  

After a successful career as a professional data analyst, backend developer, BI analyst, and data engineer, SQL remains a core technical skill with an emphasis on technical interview questions. 

Also Read: 7 SQL Interview Questions Most of Freshers Fail 

According to job trends on LinkedIn and Indeed, SQL stays among the top 5 skills in demand within tech. With companies today processing more data than ever, the need for professionals who can write efficient queries, deal with large datasets, and base their business decisions on data has only grown.   

Mastering specific SQL interview questions now asked in interviews will give you a great advantage if you are preparing for job interviews in the data/tech sectors this year.   

At Fusion Software Institute, we have compiled a list of the most asked SQL interview questions, and answers for 2025, and have updated them to be relevant, along with a matching hiring trend. Now, let's jump in and ace that prep!  

 Importance of SQL in 2025  

SQL continues to grow as one of the essential techniques in building professionalism on a data-dependent terrain, going from database maintenance to business intelligence and analytics.  

Structured data collected in large volumes by enterprises in all fields makes SQL the way for data analysts to obtain insight, write out reports, or support decisions in real-time. They say, "If a tool fits all, then it sits in the middle." It is a versatile tool, has a simple syntax, and fits well into the line of modern tools, including BigQuery, Snowflake, and Power BI.  

Data analysts, backend developers, and data engineers-the names vary as the value of a certain vocation set increases and decreases over time, it is versatility SQL brings into the picture that keeps it in demand and hence in supply.  

SQL is a primary language when working on relational databases and building dashboards; hence, any tech aspirant in 2025 will need to have it in his or her collection of languages.  

Basic SQL Interview Questions and Answers (For Freshers)  

  1. What is SQL? 

SQL is a Structured Query Language used in the computing world to access, manage, and manipulate data in relational databases like MySQL, PostgreSQL, and Oracle.   

  1. What are the types of commands available in SQL?  

SQL has five command types; Data Definition (DDL), Data Manipulation (DML), Data Control (DCL), Transaction Control (TCL), and Data Query Language (DQL).   

  1. Difference between WHERE and HAVING?  

The difference between WHERE and HAVING is that WHERE filters rows before grouping, while HAVING filters rows after you group, which is done through a GROUP BY statement in an SQL query.   

  1. What is a primary key?  

A primary key is a unique column that identifies every record in a table, it disallows NULLs and duplicate values.   

  1. What is a foreign key?  

A foreign key is a column that establishes a relationship between the two tables by allowing the value of a primary key in another table, aiding relational integrity.   

  1. What is a JOIN? List its types.  

A JOIN in SQL is used to join or combine multiple rows from differing tables, which can be INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.   

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  1. What is normalization?  

Normalization is the process of structuring the data in a way that decreases record duplication while increasing data integrity in relational databases.  

  1. What is denormalization?  

Denormalization is the act of merging tables to limit joins for performance and read value, sometimes at the cost of extra data.  

  1. What is a subquery?  

A subquery is a query that embeds inside another SQL query to return data that becomes available to the main query.  

  1. What is an alias in SQL?  

An alias is a temporary name assigned to a table and/or a column using the AS keyword in the SQL query for readability.  

Intermediate-Level SQL Interview Questions and Answers (1–3 Years Experience)  

  1. What are the differences between DELETE, TRUNCATE, and DROP?  

DELETE is used for removing selected rows, TRUNCATE removes all rows (very quickly) in a single action (without logging for each row), while DROP removes the entire structure of the table.   

  1. What is an index in SQL?  

An index can improve the performance of SQL queries by facilitating the retrieval of data from tables more quickly.   

  1. What is a view in SQL?  

A view is like a virtual table, in that it is not a table, because it is based on the result of a SQL select statement, it has no data, and it gets the data from table(s) that do contain data.   

  1. What are the differences between UNION and UNION ALL?  

UNION returns a distinct set of all the rows in a result set of a combination of two or more different queries, while UNION ALL returns all rows in a result set of a combination of two or more different queries (all of which could be the same).   

  1. What is a stored procedure?  

A stored procedure is a pre-compiled set of one or more SQL statements that can be reused to operate, such as inserting, updating, or deleting.  

  1. What is a trigger in SQL?  

Trigger is a special kind of stored procedure that auto executes when certain database events are being performed; for example, INSERT, UPDATE or DELETE.  

  1. Explain the ACID properties in SQL.  

ACID means Atomicity, Consistency, Isolation, and Durability. These properties ensure that database transactions are processed reliably.  

  1. What is a clustered index?  

A clustered index sorts and stores the actual data in the table based on the indexed column; hence fast retrieval is possible.  

  1. What is a non-clustered index?  

A non-clustered index creates an independent structure outside the table that points to the data in the table. This allows optimal flexibility of indexing.  

  1. What is the difference between BETWEEN and IN operators?  

The BETWEEN operator is used for range filtering, whereas the IN operator checks if the value exists in a group of values.  

  1. When do you use GROUP BY in SQL?  

GROUP BY statement groups rows with the same values into summary rows (like "total" or "average"). It can be used with other aggregate function statements like COUNT () or SUM ().   

  1. What is the difference between NULL, zero, or blank?  

NULL means no value or unknown, when zero is numeric and blank is just an empty string.   

  1. How to find duplicate records in a table?  

Use GROUP BY the column and filter using the HAVING COUNT (*) > 1.   

  1. What are aggregate functions in SQL?  

Aggregate functions such as COUNT (), AVG (), MAX (), and SUM () take a set of values and perform a calculation, returning a single value.   

  1. What is a window function in SQL?  

Window functions such as RANK (), ROW_NUMBER (), and LEAD () perform calculations across a set of rows related to the current row, without collapsing them into a single row.  

Advanced-Level SQL Interview Questions and Answers (3+ Years Experience)  

  1. What is the difference between RANK (), DENSE_RANK, and ROW_NUMBER ()? 

These are all window functions, but RANK () skips rank after ties, DENSE_RANK () doesn't, and ROW_NUMBER () just gives an arbitrary row number.   

  1. For what purpose is a CTE (Common Table Expression) used?  

A CTE is a temporary result set defined by using WITH. It is generally used to clarify complex queries and make them more readable.   

  1. What is meant by a recursive CTE in SQL?  

Since it calls itself, a recursive CTE is most frequently exploited for hierarchical data such as employee-manager relationships or folder structures.   

  1. What is the execution order of clauses in SQL?  

The execution order for the clauses in SQL: FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY. 

  1. Does indexing improve the performance of SQL?  

Indexes speed up SELECT queries but do ensure slow performance while INSERT, UPDATE, and DELETE operations happen due to maintenance overhead.  

  1. In what ways can you optimize SQL queries?  

In general, you can approximately optimize your SQL queries by using indexed columns in your where clause, avoiding using SELECT *, rewriting subqueries as then join your table, and checking the execution plans.  

  1. What is a transaction in SQL?  

A transaction is a series of compounding SQL operations that are executed as a unit to allow consistency and integrity.   

  1. What are SQL isolation levels?  

The isolation levels define how the application transactions are isolated, e.g. Read Uncommitted, Read Committed, Repeatable Read, and Serializable.  

  1. How would you define a deadlock in SQL and how can it be resolved?  

A deadlock occurs when two transactions are waiting indefinitely for one another to finish, it can be resolved by rolling back one of the transactions automatically.  

  1. What are some ways you can prevent SQL injection?  

You can prevent SQL injections by using parameterized queries, validating inputs to forms, and using stored procedures.  

Scenario-Based SQL Interview Questions and Answers (Real-World Use Cases)  

  1. Write a query to fetch the second-highest salary.  

Use a subquery to find the maximum salary that is less than the highest salary in the table.  

  1. Query to find employees who joined in the last 30 days.  

Filter the employee table using a condition that compares the join date to the current date minus 30 days.  

  1. Query to get a department-wise maximum salary.  

Use the GROUP BY clause on the department and apply the MAX () function on the salary column.  

  1. Find customers who placed more than 3 orders.  

Use GROUP BY on customer ID and apply a HAVING clause to count orders greater than 3.  

  1. How to find common records from two tables?  

Use either INTERSECT or INNER JOIN to retrieve records that exist in both tables based on a matching column.  

  1. Find all employees without a manager.  

Check for rows where the manager_id column is NULL, indicating the absence of a manager.  

  1. Fetch the top 3 salaries from the employee table.  

Use ORDER BY on the salary column in descending order and limit the results to the top three unique values.  

  1. Query to transpose rows into columns.  

Use conditional aggregation with the CASE WHEN statement inside aggregate functions to pivot row data into columns.  

  1. What is the difference between correlated and non-correlated subqueries?  

A correlated subquery references columns from the outer query and runs once per row, while a non-correlated subquery runs independently and only once.  

  1. Write a query to find duplicate email addresses.  

Use GROUP BY on the email column and filter with HAVING COUNT (*) > 1 to identify duplicates.  

SQL Interview Questions for Data Analysts & BI Roles (Q46–Q50)  

  1. How do you join three or more tables in SQL?  

Use multiple JOIN clauses, each connecting one table to the next using relevant foreign key relationships to combine data from all tables.  

  1. What is data integrity in SQL?  

Data integrity ensures that data remains accurate, consistent, and reliable throughout its lifecycle, enforced using constraints like primary keys, foreign keys, and unique constraints.  

  1. How do you handle missing or NULL values in SQL?  

Use functions like IS NULL, COALESCE (), or IFNULL () to detect and replace missing data with default or meaningful values.  

  1. What is the use of the CASE statement in SQL?  

CASE is used for conditional logic in SQL queries, allowing you to return different values based on specific conditions within a single column or expression.  

  1. How is SQL used in real-time analytics and reporting?  

SQL powers real-time dashboards, ad-hoc reports, and ETL pipelines by enabling fast querying, filtering, and aggregation of large data sets across business applications.  

Why Learn SQL with Fusion Software Institute?  

At Fusion Software Institute, we don't just teach you SQL - we teach you how to be successful in the field! Our trainers are industry experts who focus on giving students the skills they need through practical hands-on experience with real projects, mock interviews, and the latest SQL interview questions for 2025.  

Our curriculum is designed to give students, whether they are freshers or professionals looking to upskill, the knowledge and skill to write queries with confidence, optimize databases, and understand data relationships - the hard skills every employer is looking for.   

What makes us different is our personalized approach. Students have one-on-one mentorship with instructors, full 24/7 doubt support, and job assistance after course completion and certification - not just learning, but career ready.  

We have also tailored our course offering to support data analytics, business intelligence tools, and how SQL integrates with leading data visualization tools like Power BI and Tableau, so that students are prepared for the evolving tech sector.  

Ready to Crack Your SQL Interview in 2025?  

SQL is still an integral part of today’s data-driven decision-making, and if you know SQL it can help you obtain the highest-level roles in data analytics, backend development, or business intelligence.  

With the right preparation, you can take on even the most challenging SQL interview questions — and Fusion Software Institute is here to help.  

Get started today with expert-instructor-led training, realistic practice, and personalized career support. You could be joining the hundreds of other successful students who have made their mark in the tech world.  

Enrol now and start turning your SQL skills into a job-winning opportunity.  📞 Call 9890647273 or 7498992609