table Person
	FIO: varchar( 100 );
	BirthDate:date;
end;

table Worker (Person)
	Department:Dapartment;
end;

table Department
	Name: varchar( 100 );
	Manager: Worker;
end;

//запрос выводит ФИО всех сотрудников, их дни рождения, названия их подразделений и ФИО менеджеров отделов
select FIO, BirthDate, Department.Name, Department.Manager.FIO
from Worker

create table Person(
	UID bigint not null primary key, 
	FIO varchar( 100 ),
	BirthDate date,
	SubType, integer
)

create table Worker(
	UID bigint not null primary key, 
	Department:bigint,
	foreign key(UID) references Person(UID),
	foreign key(Department) references Department(UID) 
)

create table Department(
	UID bigint not null primary key, 
	Name varchar( 100 ),
	Manager: bigint,
	foreign key(Manager) references Worker(UID) 
)

select P.FIO, P.BirthDate, D.Name, W2.FIO
from Worker as W1
	inner join Person as P on (W1.UID=P.UID)
	left join Department as D on (W1.Department=D.UID)
	left join Worker as W2 on (D.Manager=W2.UID)