CREATE TABLE IF NOT EXISTS employees (
    employee_id INT PRIMARY KEY,
    first_name VARCHAR(50) NOT NULL,
    last_name VARCHAR(50) NOT NULL,
    department VARCHAR(50) NOT NULL,
    salary DECIMAL(10, 2) NOT NULL,
    age INT,
    city VARCHAR(50) NOT NULL
);

CREATE TABLE customers (
    customer_id INT PRIMARY KEY,
    customer_name VARCHAR(50) NOT NULL,
    email VARCHAR(50) UNIQUE NOT NULL,
    city VARCHAR(50) NOT NULL,
    total_purchase DECIMAL(10, 2) NOT NULL
);

CREATE TABLE sales (
    sale_id INT PRIMARY KEY,
    employee_id INT,
    product VARCHAR(50) NOT NULL,
    category VARCHAR(50) NOT NULL,
    quantity INT,
    price DECIMAL(10, 2) NOT NULL,
    sale_date DATE NOT NULL,
    FOREIGN KEY (employee_id) REFERENCES employees(employee_id)
);

INSERT INTO employees (employee_id, first_name, last_name, department, salary, age, city)
VALUES
(101, 'John', 'Smith', 'IT', 55000, 29, 'Manila'),
(102, 'Anna', 'Cruz', 'Finance', 42000, 31, 'Quezon City'),
(103, 'Mark', 'Santos', 'Marketing', 38000, 28, 'Pasig'),
(104, 'Maria', 'Reyes', 'HR', 45000, 36, 'Makati'),
(105, 'James', 'Garcia', 'IT', 62000, 33, 'Taguig'),
(106, 'Sarah', 'Lim', 'Finance', 35000, 27, 'Manila'),
(107, 'Daniel', 'Flores', 'Marketing', 48000, 34, 'Pasay'),
(108, 'Carla', 'Torres', 'Internship', 18000, 22, 'Caloocan'),
(109, 'Robert', 'Mendoza', 'IT', 70000, 39, 'Makati'),
(110, 'Lisa', 'Aquino', 'Training', 25000, 24, 'Pasig');

SELECT * FROM employees;