Can a view be based on another view?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of SQL & Databases conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
Yes, a view can be defined on top of another existing view (known as a nested view):
CREATE VIEW us_customers AS
SELECT * FROM Customers WHERE country = 'USA';
CREATE VIEW vip_us_customers AS
SELECT * FROM us_customers WHERE total_spend > 5000;
### Architectural Caution:
While nested views promote modular query definitions, deeply nesting views (3+ levels) can make query execution plan optimization difficult for the query planner, leading to unexpected performance bottlenecks.
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.