create database testdatabas;
use testdatabas;
create table employee (
      employee_id integer not null,
      name varchar(20),
      telephone varchar(10),
      primary key (employee_id));

      create table department (
      department_id char(1) not null,
      name varchar(20),
      boss integer,
      primary key (department_id));

      create table works_for (
      employee_id integer not null,
      department_id char(1) not null,
      primary key (employee_id, department_id));

      INSERT INTO employee (employee_id, name, telephone)
      VALUES (2, 'Arne', '463212');
      INSERT INTO employee (employee_id, name, telephone)
      VALUES (3, 'Kalle', '261456');
      INSERT INTO employee (employee_id, name, telephone)
      VALUES (4, 'Berit', '173190');
      INSERT INTO employee (employee_id, name, telephone)
      VALUES (1, 'Cecilia', '260032');
      INSERT INTO employee (employee_id, name, telephone)
      VALUES (5, 'David', '210023');
      INSERT INTO works_for (employee_id, department_id)
      VALUES (1, 'A');
      INSERT INTO works_for (employee_id, department_id)
      VALUES (1, 'B');
      INSERT INTO works_for (employee_id, department_id)
      VALUES (1, 'C');
      INSERT INTO works_for (employee_id, department_id)
      VALUES (2, 'C');
      INSERT INTO works_for (employee_id, department_id)
      VALUES (3, 'A');
      INSERT INTO works_for (employee_id, department_id)
      VALUES (4, 'B');
      INSERT INTO department (department_id, name, boss)
      VALUES ('A', 'Marknadsföring', 3);
      INSERT INTO department (department_id, name, boss)
      VALUES ('C', 'Personal', 2);
      INSERT INTO department (department_id, name, boss)
      VALUES ('B', 'Kundsupport', 4);