Question

Which of the following are multiple row functions?
(A) Sum
(B) Count
(C) Left
(D) Max
Choose the correct answer from the options given below:

• A. (A), (B) and (C) only
• B. (A) and (D) only
• C. (A), (B) and (D) only
• D. (A) and (B) only

Hint:

Common multiple-row (aggregate) functions include: SUM(), AVG(), COUNT(), MAX(), and MIN().
String, mathematical, and date functions (like LEFT, ROUND, NOW) are single-row functions.

Answer 1

The Correct Option is C

Concept:
SQL functions are broadly categorized into two major types:
1. Single Row (Scalar) Functions: Operate on a single value per row and return a single calculated value for each row.
2. Multiple Row (Aggregate) Functions: Accept values from multiple rows of a column as input and produce a single combined summary result.

Step 1: Evaluating the Given Functions:
- SUM(): Computes the total sum of numerical values across multiple rows. This is an aggregate/multiple row function.
- COUNT(): Returns the count of rows that match a specified criterion across multiple records. This is a multiple row function.
- LEFT(): Extracts a specified number of characters starting from the left side of an individual string. It operates independently on each row's string value, making it a single-row string function.
- MAX(): Scans multiple rows of a given column to determine and return the maximum value. This is a multiple row function.

Step 2: Identifying Multiple Row Functions:
From the above breakdown, (A) SUM, (B) COUNT, and (D) MAX are multiple row functions, whereas (C) LEFT is a single row scalar function.
Final Answer:
The correct combination is (A), (B) and (D) only, represented by option (C).