Mock interview practice

SQL Developer interview questions & mock practice

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What interview questions are asked for an SQL Developer?

An SQL Developer interview in 2026 runs across 4 rounds — core sql round, procedures & t-sql/pl-sql, optimisation round, design & scenario. Below are the most-asked SQL Developer interview questions and a focused prep plan. Rehearse every answer out loud with the free timed practice below before the real one.

  • SQL
  • Stored Procedures
  • Query Optimisation
  • Indexing
  • PL/SQL
  • Database Design
  • Triggers

Free interview practice · SQL Developer

Practise your SQL Developer interview now — free

Step through the 12 most-asked SQL Developer questions one at a time, under a timer, just like the real thing. Jot your answer, then reveal what a strong answer covers. No signup needed to practise.

Interview rounds

The SQL Developer interview process

Advanced SQL, stored procedures, query tuning and database design — the SQL-developer interview for backend, BI and database teams.

1. Core SQL round

Joins, aggregations, subqueries and window functions.

2. Procedures & T-SQL/PL-SQL

Stored procedures, functions, triggers and cursors.

3. Optimisation round

Indexing, execution plans and query tuning.

4. Design & scenario

Schema design, normalisation and a practical query problem.

Most-asked questions

Most-asked SQL Developer interview questions

12 of the questions SQL Developer candidates are asked most often in India. Practise answering each one out loud in the timed practice above.

  1. 1. What is the difference between INNER, LEFT, RIGHT and FULL OUTER JOIN?
  2. 2. Write a query to find the second-highest salary in a table.
  3. 3. What is the difference between WHERE and HAVING?
  4. 4. Explain window functions like ROW_NUMBER(), RANK() and DENSE_RANK().
  5. 5. What is the difference between a stored procedure and a function?
  6. 6. What is database indexing, and what is the difference between clustered and non-clustered indexes?
  7. 7. Explain the difference between DELETE, TRUNCATE and DROP.
  8. 8. What is a CTE, and how does a recursive CTE work?
  9. 9. What are the ACID properties, and what are transaction isolation levels?
  10. 10. How do you find and remove duplicate rows in a table?
  11. 11. What is the difference between UNION and UNION ALL?
  12. 12. How would you optimise a slow-running query?
How to prepare

How to prepare for your SQL Developer interview

Be fluent in joins, GROUP BY, subqueries, CTEs and window functions — write them quickly and correctly.

Know the difference between DELETE/TRUNCATE/DROP, clustered vs non-clustered indexes, and UNION vs UNION ALL.

Practice writing stored procedures, functions and triggers in your dialect (T-SQL or PL/SQL).

Understand query optimisation: how indexes work, reading execution plans and avoiding table scans.

Be ready to design a normalised schema and write tricky queries (Nth highest, duplicates, running totals) under time pressure.

Practise other roles

Interview prep guides

SQL Developer interview — FAQs

What questions are asked in an SQL Developer interview?

Common SQL Developer interview questions include: What is the difference between INNER, LEFT, RIGHT and FULL OUTER JOIN? Write a query to find the second-highest salary in a table. What is the difference between WHERE and HAVING? Explain window functions like ROW_NUMBER(), RANK() and DENSE_RANK(). Interviews usually run across 4 rounds — Core SQL round, Procedures & T-SQL/PL-SQL, Optimisation round, Design & scenario. Practise them with the free timed practice on this page.

How many rounds are in an SQL Developer interview?

A typical SQL Developer interview has 4 rounds: Core SQL round (Joins, aggregations, subqueries and window functions.); Procedures & T-SQL/PL-SQL (Stored procedures, functions, triggers and cursors.); Optimisation round (Indexing, execution plans and query tuning.); Design & scenario (Schema design, normalisation and a practical query problem.).

How do I prepare for an SQL Developer interview?

To prepare for an SQL Developer interview: Be fluent in joins, GROUP BY, subqueries, CTEs and window functions — write them quickly and correctly. Know the difference between DELETE/TRUNCATE/DROP, clustered vs non-clustered indexes, and UNION vs UNION ALL. Practice writing stored procedures, functions and triggers in your dialect (T-SQL or PL/SQL). Then rehearse every question out loud with the timed practice on this page before the real thing.

What skills do I need for an SQL Developer role?

Core SQL Developer skills tested in interviews include SQL, Stored Procedures, Query Optimisation, Indexing, PL/SQL, Database Design, Triggers. OnJob shows you exactly which of these skills stand between you and a 100% match on every live SQL Developer job.

Is the SQL Developer mock interview practice free?

Yes. The questions, the answer guidance and the timed practice on this page are free and need no signup. With a free OnJob account you can also take timed role tests and free certification tests. Personalised AI role and skill tests are part of the paid plans.

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Ace your SQL Developer interview

Rehearse every SQL Developer question out loud on this page, then sign in to take a timed role test or a free certification in the OnJob practice hub.

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