Post #2434

Today, let's understand SQL JOINS in detail:📝 SQL JOINs are used to combine rows from two or more tables based on related columns. 🟢 1. INNER JOIN Returns only the matching rows from both tables. Example: SELECT Employees.name, Departments.dept_name FROM Employees INNER JOIN Departments ON Employees.dept_id = Departments.id; 📌Use Case: Employees with assigned departments only. 🔵 2. LEFT JOIN (LEFT OUTER JOIN) Returns all rows from the left table, and matching rows from the right table. If no match, returns NULL. Example: SELECT Employees.name, Departments.dept_name FROM Employees LEFT JOIN Departments ON Employees.dept_id = Departments.id; 📌Use Case: All employees, even those without a department. 🟠 3. RIGHT JOIN (RIGHT OUTER JOIN) Returns all rows from the right table, and matching rows from the left table. If no match, returns NULL. Example: SELECT Employees.name, Departments.dept_name FROM Employees RIGHT JOIN Departments ON Employees.dept_id = Departments.id; 📌Use Case: All departments, even those without employees. 🔴 4. FULL OUTER JOIN Returns all rows from both tables. Non-matching rows show NULL. Example: SELECT Employees.name, Departments.dept_name FROM Employees FULL OUTER JOIN Departments ON Employees.dept_id = Departments.id; 📌Use Case: See all employees and departments, matched or not. 📝Tips: ⦁ Always specify the join condition (ON) ⦁ Use table aliases to simplify long queries ⦁ NULLs can appear if there's no match in a join 📌 SQL Roadmap: https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v/1506 💬Double Tap ❤️ For More!