[Solved] Find the problem in this query:SELECT d.name, e.name FROM departments d RIGHT JOIN employees e ON d.id = e.dept_id ORDER BY d.name;Given that some employees have no matching department. | PostgreSQL

PostgreSQL - Joins in PostgreSQL

Find the problem in this query:

SELECT d.name, e.name FROM departments d RIGHT JOIN employees e ON d.id = e.dept_id ORDER BY d.name;

Given that some employees have no matching department.

ARIGHT JOIN should be LEFT JOIN to keep all departments

BOrdering by d.name will put NULLs first, causing confusion

CON condition is missing

DEmployees table should be on left side

Step-by-Step Solution

Solution:

Step 1: Understand RIGHT JOIN result
RIGHT JOIN keeps all employees. Some employees have no matching department, so d.name is NULL for them.
Step 2: Effect of ORDER BY d.name
Ordering by d.name will place NULL values first by default, which may confuse output order.
Final Answer:
Ordering by d.name with NULLs can cause unexpected order. -> Option B
Quick Check:
ORDER BY column with NULLs can affect result order [OK]

Quick Trick: ORDER BY columns with NULLs may reorder rows unexpectedly [OK]

Common Mistakes:

Assuming RIGHT JOIN is wrong here
Missing ON condition (it is present)
Thinking table order must change

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Find the problem in this query:

Step 1: Understand RIGHT JOIN result

Step 2: Effect of ORDER BY d.name

Final Answer:

Quick Check:

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