[Solved] Given tables Employees and Departments, what will this query return?SELECT Employees.name, Departments.name FROM Employees LEFT JOIN Departments ON Employees.dept_id = Departments.id; | SQL

SQL - LEFT and RIGHT JOIN

Given tables Employees and Departments, what will this query return?

SELECT Employees.name, Departments.name FROM Employees LEFT JOIN Departments ON Employees.dept_id = Departments.id;

AOnly departments that have employees.

BAll employees with their department names; NULL if no department assigned.

CAll departments with their employees; NULL if no employee assigned.

DOnly employees who have a matching department.

Step-by-Step Solution

Solution:

Step 1: Understand LEFT JOIN effect on Employees and Departments
LEFT JOIN keeps all rows from Employees (left table) and matches Departments (right table). If no match, department columns are NULL.
Step 2: Analyze query output
Query returns all employees with their department names or NULL if no department assigned.
Final Answer:
All employees with their department names; NULL if no department assigned. -> Option B
Quick Check:
LEFT JOIN output = D [OK]

Quick Trick: LEFT JOIN keeps all left rows, unmatched right columns are NULL [OK]

Common Mistakes:

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Given tables Employees and Departments, what will this query return?