MySQL + SQL · Lesson 68

LEFT JOIN and RIGHT JOIN

LEFT JOIN

LEFT JOIN returns ALL rows from the left table, plus matching rows from the right. Where there is no match, right columns are NULL.
SELECT s.name, c.class_name
FROM students s
LEFT JOIN classes c ON s.class_id = c.class_id;
Every student appears; those without a class show NULL for class_name.
RIGHT JOIN is the mirror: ALL rows from the right table, plus matches from the left.
SELECT s.name, c.class_name
FROM students s
RIGHT JOIN classes c ON s.class_id = c.class_id;
Every class appears, even classes with no students.

Summary

  • LEFT JOIN keeps all left-table rows; RIGHT JOIN keeps all right-table rows.
  • Missing matches become NULL.
🔗

Share this topic with a friend

यह topic किसी दोस्त को भेजें

Found it useful? Send it to a classmate learning the same thing.

अच्छा लगा? जो दोस्त यही सीख रहा है, उसे भेज दीजिए।

💻 Live Code Editor

This page's programs are ready here — run them, edit them, and learn. No installation needed.
Powered by OneCompiler. The code loads into the editor automatically — press Run to see the output. If the editor does not open, open it in a new tab.