Why is it important to understand the difference between INNER JOIN and LEFT JOIN when working with related tables?

hard📝 Conceptual Q10 of 15

SQL - Table Relationships

ABecause LEFT JOIN is faster than INNER JOIN

BBecause INNER JOIN can only join two tables, LEFT JOIN can join many

CBecause INNER JOIN returns only matching rows, LEFT JOIN returns all from left table

DBecause LEFT JOIN deletes unmatched rows automatically

Step-by-Step Solution

Solution:

Step 1: Define INNER JOIN behavior
INNER JOIN returns rows where keys match in both tables.
Step 2: Define LEFT JOIN behavior
LEFT JOIN returns all rows from left table, matching or not.
Final Answer:
Because INNER JOIN returns only matching rows, LEFT JOIN returns all from left table -> Option C
Quick Check:
INNER vs LEFT JOIN difference = Because INNER JOIN returns only matching rows, LEFT JOIN returns all from left table [OK]

Quick Trick: INNER JOIN matches both tables; LEFT JOIN keeps all left rows [OK]

Common Mistakes:

MISTAKES

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