Subquery_vs_Join.md

CREATE TABLE departments (
	id INT NOT NULL AUTO_INCREMENT,
	name VARCHAR(255) NOT NULL,
	PRIMARY KEY(id)
);

CREATE TABLE employees (
	id INT NOT NULL AUTO_INCREMENT,
	name VARCHAR(255) NOT NULL,
	department_id INT NOT NULL,
	PRIMARY KEY(id),
	FOREIGN KEY (department_id) REFERENCES departments(id) ON DELETE CASCADE
);

INSERT INTO departments (name) VALUES ('Administration'), ('Sales');
INSERT INTO employees (name, department_id) VALUES ('John Doe', 1), ('Jane Doe', 1), ('Janie Doe', 2), ('Johnny  Doe', 2);


SELECT id, name FROM employees WHERE department_id = (SELECT id FROM departments WHERE name = 'Sales');
SELECT e.id, e.name FROM employees e JOIN departments d ON e.department_id = d.id WHERE d.name = "Sales";