Select records where FirstName="John" AND LastName="Jackson"?
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
To retrieve records that satisfy multiple simultaneous criteria, use the AND logical conjunction operator:
SELECT *
FROM Customers
WHERE FirstName = 'John'
AND LastName = 'Jackson';
### Optimization Tip:
When frequently querying by both columns, create a composite index on (LastName, FirstName):
CREATE INDEX idx_customers_name ON Customers(LastName, FirstName);
Composite B-tree indexes allow the database engine to locate the exact record in $O(\log n)$ lookup time.
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.