Post #2306

SQL Joins Made Easy🧠☑️ ● INNER JOIN – Returns only matching rows from both tables 🧩 Think: Intersection Example: SELECT * FROM orders INNER JOIN customers ON orders.customer_id = customers.id; ● LEFT JOIN (LEFT OUTER JOIN) – All rows from left table + matching from right (NULL if no match) 🔍 Think: All from Left, matching from Right Example: SELECT * FROM customers LEFT JOIN orders ON customers.id = orders.customer_id; ● RIGHT JOIN (RIGHT OUTER JOIN) – All rows from right table + matching from left (NULL if no match) 🧭 Think: All from Right, matching from Left Example: SELECT * FROM orders RIGHT JOIN customers ON orders.customer_id = customers.id; ● FULL JOIN (FULL OUTER JOIN) – All rows from both tables, matching where possible 🌐 Think: Union of both Example: SELECT * FROM customers FULL OUTER JOIN orders ON customers.id = orders.customer_id; ● CROSS JOIN – Cartesian product of every row in A × every row in B ♾️ Use carefully! Example: SELECT * FROM colors CROSS JOIN sizes; ● SELF JOIN – Join a table to itself using aliases 🔄 Useful for hierarchical data Example: SELECT e1.name AS Employee, e2.name AS Manager FROM employees e1 LEFT JOIN employees e2 ON e1.manager_id = e2.id; 💡Remember: Use JOIN ON common_column to link tables correctly! Double Tap ♥️ For More