[Solved] What does a LEFT JOIN do in SQL? — Ans: Keeps all rows from the left table and adds matching rows from the right table... | SQL

SQL - LEFT and RIGHT JOIN

What does a LEFT JOIN do in SQL?

ADeletes rows from the left table that have no match in the right table.

BKeeps only rows that have matches in both tables.

CKeeps all rows from the right table and adds matching rows from the left table.

DKeeps all rows from the left table and adds matching rows from the right table or NULL if no match.

Step-by-Step Solution

Solution:

Step 1: Understand LEFT JOIN behavior
A LEFT JOIN returns all rows from the left table regardless of matches in the right table.
Step 2: Check what happens with unmatched rows
If there is no matching row in the right table, the result shows NULL for right table columns.
Final Answer:
Keeps all rows from the left table and adds matching rows from the right table or NULL if no match. -> Option D
Quick Check:
LEFT JOIN = all left rows kept [OK]

Quick Trick: Remember: LEFT JOIN keeps all left rows, fills right with NULL if no match [OK]

Common Mistakes:

MISTAKES

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What does a LEFT JOIN do in SQL?