[Solved] Why does the SQL AVG() function ignore NULL values when calculating the average? — Ans: Because NULL means unknown, so it is excluded from calculations | SQL

SQL - Aggregate Functions

Why does the SQL AVG() function ignore NULL values when calculating the average?

ABecause NULL values cause AVG() to return NULL always

BBecause NULL is treated as zero in AVG()

CBecause AVG() only works on non-nullable columns

DBecause NULL means unknown, so it is excluded from calculations

Step-by-Step Solution

Solution:

Step 1: Understand NULL meaning in SQL
NULL represents unknown or missing data, not zero or any number.
Step 2: AVG() ignores NULL to avoid skewing results
Including NULL as zero would lower average incorrectly, so NULLs are excluded.
Final Answer:
Because NULL means unknown, so it is excluded from calculations -> Option D
Quick Check:
NULL excluded in AVG() because it's unknown [OK]

Quick Trick: NULL means unknown, so AVG() skips it [OK]

Common Mistakes:

MISTAKES

Master "Aggregate Functions" in SQL

9 interactive learning modes - each teaches the same concept differently

More SQL Quizzes

Why does the SQL AVG() function ignore NULL values when calculating the average?