SQL Join Examples in MySQL

Practical Join Queries

List Students with Class Names

SELECT s.name, c.class_name
FROM students s
JOIN classes c ON s.class_id = c.class_id;

Fees Paid by Each Student

SELECT s.name, SUM(f.amount) AS total_paid
FROM students s
JOIN fees f ON s.roll_no = f.roll_no
GROUP BY s.name;

Three-Table Join

SELECT s.name, c.class_name, f.amount
FROM students s
JOIN classes c ON s.class_id = c.class_id
JOIN fees f ON s.roll_no = f.roll_no;

Summary

• JOIN + GROUP BY summarises related data (e.g. total fees per student).
• Chain multiple JOINs to combine three or more tables.

Practical Join Queries

Students को Class Names के साथ List करें

SELECT s.name, c.class_name
FROM students s
JOIN classes c ON s.class_id = c.class_id;

हर Student की Fees

SELECT s.name, SUM(f.amount) AS total_paid
FROM students s
JOIN fees f ON s.roll_no = f.roll_no
GROUP BY s.name;

तीन-Table Join

SELECT s.name, c.class_name, f.amount
FROM students s
JOIN classes c ON s.class_id = c.class_id
JOIN fees f ON s.roll_no = f.roll_no;

सारांश

• JOIN + GROUP BY related data summarise करता है (जैसे हर student की कुल fees)।
• तीन या ज़्यादा tables के लिए कई JOINs chain करें।