Question

Match List-I with List-II:

List-I (Aggregate function)	List-II (Description)
(A) count(marks)	(III) Count all non null values of marks column
(B) count()	(I) Count all rows
(C) avg(marks)	(II) Finding average of non null values of marks
(D) sum(marks)	(IV) Finding sum of all marks

• A. (A)-(III), (B)-(I), (C)-(II), (D)-(IV)
• B. (A)-(I), (B)-(III), (C)-(II), (D)-(IV)
• C. (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
• D. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

Hint:

Remember: - COUNT() counts all rows. - COUNT(column) ignores NULL values. - AVG() and SUM() both ignore NULL values while performing calculations.

Answer 1

The Correct Option is A

Step 1: Understanding aggregate functions.
- count(marks) → Counts only non-null entries in the column “marks”. Corresponds to (III).
- count() → Counts all rows in the table, including those with NULL values. Corresponds to (I).
- avg(marks) → Calculates the average of all non-null values of “marks”. Corresponds to (II).
- sum(marks) → Returns the total sum of all non-null values of “marks”. Corresponds to (IV).

Step 2: Matching.
Therefore, the correct matching is: (A) → (III), (B) → (I), (C) → (II), (D) → (IV).
Final Answer: \[ \boxed{\text{Option (1)}} \]