/*Найти однофамильцев (первый способ)*/
select e1.EmployeeKey, e2.EmployeeKey, e1.LastName, e2.LastName
from DimEmployee as e1, DimEmployee as e2
where e1.LastName = e2.LastName And e1.EmployeeKey < e2.EmployeeKey
order by e1.EmployeeKey, e2.EmployeeKey


/*Найти однофамильцев (второй способ)*/
select distinct 'k'=e1.EmployeeKey, 'l'=e1.LastName
from DimEmployee as e1, DimEmployee as e2
where e1.LastName = e2.LastName And e1.EmployeeKey <> e2.EmployeeKey
and e1.Status is not null and e2.Status is not null 
order by e1.LastName, e1.EmployeeKey