INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN are different SQL join types, each with its distinct characteristics.

Join Types at a Glance

• INNER JOIN: Returns matching records from both tables.
• LEFT JOIN: Retrieves all records from the left table and matching ones from the right.
• RIGHT JOIN: Gets all records from the right table and matching ones from the left.
• FULL JOIN: Includes all records when there is a match in either of the tables.

Visual Representation

Code Example: SQL Joins

Here is the SQL code:

-- CREATE TABLES
CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(100),
    department_id INT
);

CREATE TABLE departments (
    id INT PRIMARY KEY,
    name VARCHAR(100)
);

-- INSERT SOME DATA
INSERT INTO employees (id, name, department_id) VALUES
  (1, 'John', 1), 
  (2, 'Alex', 2), 
  (3, 'Lisa', 1), 
  (4, 'Mia', 1);

INSERT INTO departments (id, name) VALUES 
  (1, 'HR'), 
  (2, 'Finance'), 
  (3, 'IT');

-- INNER JOIN
SELECT employees.name, departments.name as department
FROM employees
INNER JOIN departments ON employees.department_id = departments.id;

-- LEFT JOIN
SELECT employees.name, departments.name as department
FROM employees
LEFT JOIN departments ON employees.department_id = departments.id;

-- RIGHT JOIN
SELECT employees.name, departments.name as department
FROM employees
RIGHT JOIN departments ON employees.department_id = departments.id;

-- FULL JOIN
SELECT employees.name, departments.name as department
FROM employees
FULL JOIN departments ON employees.department_id = departments.id;