[Solved] What is the main difference between a FULL OUTER JOIN and a LEFT JOIN in SQL? — Ans: FULL OUTER JOIN returns all rows from both tables, LEFT JOIN returns all rows... | SQL

SQL - Advanced Joins

What is the main difference between a FULL OUTER JOIN and a LEFT JOIN in SQL?

AFULL OUTER JOIN returns all rows from both tables, LEFT JOIN returns all rows from the left table only.

BFULL OUTER JOIN returns only matching rows, LEFT JOIN returns all rows from the right table.

CFULL OUTER JOIN returns only rows from the right table, LEFT JOIN returns all rows from both tables.

DFULL OUTER JOIN returns rows only when there is no match, LEFT JOIN returns only matching rows.

Step-by-Step Solution

Solution:

Step 1: Understand LEFT JOIN behavior
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 FULL OUTER JOIN behavior
FULL OUTER JOIN returns all rows from both tables, matching where possible, and NULLs where no match exists on either side.
Final Answer:
FULL OUTER JOIN returns all rows from both tables, LEFT JOIN returns all rows from the left table only. -> Option A
Quick Check:
FULL OUTER JOIN vs LEFT JOIN = A [OK]

Quick Trick: FULL OUTER JOIN keeps all rows from both tables [OK]

Common Mistakes:

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What is the main difference between a FULL OUTER JOIN and a LEFT JOIN in SQL?