[Solved] What is the main difference between a LEFT JOIN and a RIGHT JOIN in PostgreSQL? — Ans: LEFT JOIN returns all rows from the left table, RIGHT JOIN returns all rows... | PostgreSQL

PostgreSQL - Joins in PostgreSQL

What is the main difference between a LEFT JOIN and a RIGHT JOIN in PostgreSQL?

ALEFT JOIN returns all rows from the left table, RIGHT JOIN returns all rows from the right table.

BLEFT JOIN returns only matching rows, RIGHT JOIN returns all rows from both tables.

CLEFT JOIN returns all rows from the right table, RIGHT JOIN returns all rows from the left table.

DLEFT JOIN and RIGHT JOIN return the same results but in different order.

Step-by-Step Solution

Solution:

Step 1: Understand LEFT JOIN behavior
A LEFT JOIN returns all rows from the left table and matching rows from the right table. If no match, right side columns are NULL.
Step 2: Understand RIGHT JOIN behavior
A RIGHT JOIN returns all rows from the right table and matching rows from the left table. If no match, left side columns are NULL.
Final Answer:
LEFT JOIN returns all rows from the left table, RIGHT JOIN returns all rows from the right table. -> Option A
Quick Check:
Difference between LEFT and RIGHT JOIN = LEFT returns left table rows, RIGHT returns right table rows [OK]

Quick Trick: LEFT JOIN keeps left table rows; RIGHT JOIN keeps right table rows [OK]

Common Mistakes:

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What is the main difference between a LEFT JOIN and a RIGHT JOIN in PostgreSQL?