Technical screening questions
Ask for one example per question and listen for specifics.
- How do you read an execution plan? A good answer: Spots scans, key lookups and expensive operators.
- What is the difference between a clustered and nonclustered index? A good answer: Physical ordering versus separate structures.
- How do you find duplicates in a table? A good answer: GROUP BY with HAVING or window functions.
- What are CTEs and window functions used for? A good answer: Readability and ranking or running totals.
- How do you manage transactions and locking? A good answer: Isolation levels and avoiding long transactions.
Quick screening questions
Use these when you have only a few minutes.
- How do you read an execution plan?
- Describe a query you reduced from minutes to seconds.
- How do you handle deadlocks?
What separates the levels
Match the level to the requirement before you submit.
- Junior: writes queries and procedures.
- Mid: designs schemas and tunes.
- Senior: owns data architecture and performance.
Red flags
Any of these is a reason to probe further.
- Only simple SELECT statements.
- Cannot discuss indexing.
- Has not read an execution plan.
Tools you should hear mentioned
An SQL developer with real experience usually names several of these without prompting.
- T-SQL or PL/SQL
- SQL Server Management Studio
- Execution plans
- Indexes and statistics
- SSIS or ETL tools
- Version control for scripts
Run the call well
Ask for the last project first, then dig into the second or third question. Take notes on versions, team size and outcomes, and record them with the submission so the vendor’s later technical interview does not surprise you.
Frequently asked questions
How long should an SQL developer screening call take?
Fifteen to twenty minutes is enough to cover the project, three technical questions and availability, rate and work authorization.
Do recruiters need to know the technology?
Working vocabulary is enough. Use the sourcing guide for the role and listen for specifics instead of judging technical depth yourself.