[Solved] Given the table employees with columns id, name, and manager_id, what will this query return?SELECT e1.name AS Employee, e2.name AS Manager FROM employees e1 LEFT JOIN employees e2 ON e1.... | SQL

SQL - INNER JOIN

Given the table employees with columns id, name, and manager_id, what will this query return?

SELECT e1.name AS Employee, e2.name AS Manager FROM employees e1 LEFT JOIN employees e2 ON e1.manager_id = e2.id;

ASyntax error due to missing WHERE clause

BList of employees with their managers' names, NULL if no manager

CList of employees without managers only

DList of managers with their employees' names

Step-by-Step Solution

Solution:

Step 1: Understand the LEFT JOIN on self join
The query joins the employees table to itself using aliases e1 and e2, matching e1.manager_id to e2.id to find each employee's manager.
Step 2: Interpret the SELECT columns and join type
Using LEFT JOIN means all employees (e1) appear, even if they have no manager (e2.name will be NULL). The SELECT shows employee and manager names.
Final Answer:
List of employees with their managers' names, NULL if no manager -> Option B
Quick Check:
LEFT JOIN self join shows all employees with managers [OK]

Quick Trick: LEFT JOIN keeps all employees, shows NULL for missing managers [OK]

Common Mistakes:

MISTAKES

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