Why does placing a WHERE right_table.col = 'value' filter break a LEFT JOIN?

It triggers a syntax parsing crash.

The WHERE clause filters out the NULLs generated by unmatched rows, converting the query into an INNER JOIN.

WHERE clauses are not allowed in joins.

easy #sql #postgresql #retail

QUESTION 01 OF 02

LEFT JOIN & RIGHT JOIN

Quiz for lesson: LEFT JOIN & RIGHT JOIN

Taken by 0 developers

Answered 0/2

Pass 70%

~3 min

00:00

Note: Sign in to save your quiz progress and results.

What happens to rows in the left table that have no matching rows in the right table during a LEFT JOIN?

About this Quiz

This interactive assessment is designed to test your understanding of LEFT JOIN & RIGHT JOIN. Whether you are a beginner looking to grasp the basics or an experienced professional aiming to refine your skills, quizzes are an excellent way to validate your knowledge and identify areas for improvement.

Instructions

Read each question carefully before answering.
Some questions may have multiple correct answers.
There is no time limit, so take your time to think.
You will receive immediate feedback after submission.

Learning Outcomes

Self-assess your current skill level.
Reinforce key concepts through active recall.
Identify knowledge gaps to focus your study.
Gain confidence in your technical expertise.
Reinforce memory and recall.