[Solved] What will be the output of this query?SELECT * FROM (VALUES (10, 'X'), (20, 'Y')) AS t(num, letter) WHERE num > 15; | PostgreSQL

PostgreSQL - Set Operations and Advanced Queries

What will be the output of this query?

SELECT * FROM (VALUES (10, 'X'), (20, 'Y')) AS t(num, letter) WHERE num > 15;

A10 | X

B20 | Y

C10 | X and 20 | Y

DNo rows returned

Step-by-Step Solution

Solution:

Step 1: Understand the VALUES data and aliasing
The VALUES clause creates two rows: (10, 'X') and (20, 'Y') with columns num and letter.
Step 2: Apply the WHERE filter num > 15
Only the row with num = 20 satisfies the condition, so only that row is returned.
Final Answer:
20 | Y -> Option B
Quick Check:
Filter num > 15 returns only 20 | Y [OK]

Quick Trick: WHERE filters rows after VALUES inline data [OK]

Common Mistakes:

Master "Set Operations and Advanced Queries" in PostgreSQL

9 interactive learning modes - each teaches the same concept differently

What will be the output of this query?