Solution:Step 1: Understand SUM() behavior with no matching rowsIf no rows match the WHERE condition, SUM() returns NULL.Step 2: Check other optionsPrice with text would cause error, SUM() works with WHERE, and table missing causes error, not NULL.Final Answer:There are no rows with Category = 'Elec

[Solved] Consider this query:SELECT SUM(Price) FROM Products WHERE Category = 'Electronics'It returns NULL instead of a number. What is the most likely cause? | SQL

SQL - Aggregate Functions

Consider this query:
SELECT SUM(Price) FROM Products WHERE Category = 'Electronics'
It returns NULL instead of a number. What is the most likely cause?

AThere are no rows with Category = 'Electronics'

BThe Price column contains text values

CSUM() cannot be used with WHERE clause

DThe table Products does not exist

Step-by-Step Solution

Solution:

Step 1: Understand SUM() behavior with no matching rows
If no rows match the WHERE condition, SUM() returns NULL.
Step 2: Check other options
Price with text would cause error, SUM() works with WHERE, and table missing causes error, not NULL.
Final Answer:
There are no rows with Category = 'Electronics' -> Option A
Quick Check:
SUM() returns NULL if no rows match [OK]

Quick Trick: SUM() returns NULL if no rows match WHERE [OK]

Common Mistakes:

MISTAKES

Assuming SUM() returns 0 when no rows match
Thinking SUM() fails with WHERE clause
Ignoring NULL result meaning no data

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Consider this query:

Step 1: Understand SUM() behavior with no matching rows

Step 2: Check other options

Final Answer:

Quick Check:

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