[Solved] This SQL query is intended to find all courses taken by student with ID 3:SELECT c.Name FROM Course c JOIN StudentCourse sc ON c.ID = sc.CourseID WHERE sc.... | SQL

SQL - Table Relationships

This SQL query is intended to find all courses taken by student with ID 3:

SELECT c.Name FROM Course c JOIN StudentCourse sc ON c.ID = sc.CourseID WHERE sc.StudentID = 3;

But it returns no rows even though student 3 exists and has courses. What is the likely error?

AThe junction table has no matching records for student 3.

BThe WHERE clause filters on a non-existent student ID.

CThe join condition uses wrong columns.

DThe Course table has no matching course IDs.

Step-by-Step Solution

Solution:

Step 1: Check join and filter logic
The join and WHERE clause are correct for filtering courses by student ID.
Step 2: Consider data in junction table
If no rows return, likely the junction table lacks entries for student 3, even if student exists.
Final Answer:
The junction table has no matching records for student 3. -> Option A
Quick Check:
No junction records = no results [OK]

Quick Trick: No junction records means no join results [OK]

Common Mistakes:

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