Solution:Step 1: Use self join on employees tableJoin employees table to itself matching e.manager_id to m.id to get manager info.Step 2: Select employee and manager namesAlias tables as e and m, select e.name and m.name with aliases for clarity.Final Answer:SELECT e.name AS employee, m.name AS mana

[Solved] Given tables:employees(id, name, manager_id)Write a query to list employee names with their manager names using INNER JOIN. | PostgreSQL

PostgreSQL - Joins in PostgreSQL

Given tables:
employees(id, name, manager_id)
Write a query to list employee names with their manager names using INNER JOIN.

ASELECT e.name, m.name FROM employees e LEFT JOIN employees m ON e.manager_id = m.id;

BSELECT e.name, m.name FROM employees e INNER JOIN managers m ON e.manager_id = m.id;

CSELECT e.name, m.name FROM employees e INNER JOIN employees m ON e.id = m.manager_id;

DSELECT e.name AS employee, m.name AS manager FROM employees e INNER JOIN employees m ON e.manager_id = m.id;

Step-by-Step Solution

Solution:

Step 1: Use self join on employees table
Join employees table to itself matching e.manager_id to m.id to get manager info.
Step 2: Select employee and manager names
Alias tables as e and m, select e.name and m.name with aliases for clarity.
Final Answer:
SELECT e.name AS employee, m.name AS manager FROM employees e INNER JOIN employees m ON e.manager_id = m.id; -> Option D
Quick Check:
Self join employees on manager_id = id for manager names [OK]

Quick Trick: Self join employees on manager_id to get manager names [OK]

Common Mistakes:

Using LEFT JOIN instead of INNER JOIN
Joining on wrong columns
Referencing non-existent managers table

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Given tables:

Step 1: Use self join on employees table

Step 2: Select employee and manager names

Final Answer:

Quick Check:

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