Databases · SQL
Official IIT answer key · IIT Delhi · Audited Aug 2026
GATE CSE 2020 Q13 · MCQ · 1 mark
SELECT s.sno, s.sname
FROM Suppliers s, Catalogue c
WHERE s.sno = c.sno AND
cost > (SELECT AVG (cost)
FROM Catalogue
WHERE pno = 'P4'
GROUP BY pno);
The number of rows returned by the above SQL query is
Key concept
Topic notes
In GATE CS, SQL is tested through a balanced mix of declarative query semantics, relational-algebra correspondence, subquery evaluation (correlated, nested, and universal quantification), and instance-level tracing. Questions range from conceptual integrity rules (DDL constraints, FOREIGN KEY targets, GROUP BY/HAVING rules) to practical computation of output row counts and aggregate values on small database instances. Recent papers strongly emphasize NAT execution traces and multi-correct (MSQ) equivalent query formulations.
Full SQL guide →Independent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.