[Solved] Why does a window function not reduce the number of rows returned, unlike GROUP BY? — Ans: Because window functions compute values across rows but keep each original row... | SQL

SQL - Window Functions Fundamentals

Why does a window function not reduce the number of rows returned, unlike GROUP BY?

ABecause window functions automatically remove duplicates.

BBecause window functions only work on indexed columns.

CBecause window functions require a HAVING clause.

DBecause window functions compute values across rows but keep each original row intact.

Step-by-Step Solution

Solution:

Step 1: Understand window function behavior
Window functions calculate aggregates or rankings over a set of rows but do not group or collapse rows.
Step 2: Contrast with GROUP BY
GROUP BY aggregates rows into groups, reducing the number of rows returned.
Final Answer:
Because window functions compute values across rows but keep each original row intact. -> Option D
Quick Check:
Window functions keep rows; GROUP BY reduces rows = C [OK]

Quick Trick: Window functions keep rows; GROUP BY collapses them [OK]

Common Mistakes:

Master "Window Functions Fundamentals" in SQL

9 interactive learning modes - each teaches the same concept differently

More SQL Quizzes

Why does a window function not reduce the number of rows returned, unlike GROUP BY?