Create View V1 as
Select ΚΩΔΑΝΑΓ, count(ΚΩΔΔΑΝ)as PLHTHOS1
From ΔΑΝΕΙΣΜΟΙ
Group by ΚΩΔΑΝΑΓ
Create View V2 as
Select ΚΩΔΑΝΑΓ, ΕΠΙΘΕΤΟ , ΟΝΟΜΑ, ΤΗΛ, PLHTHOS1
From ΔΑΝΕΙΣΜΟΙ, V1
Where ΔΑΝΕΙΣΜΟΙ.ΚΩΔΑΝΑΓ= V1.ΚΩΔΑΝΑΓ
Order by PLHTHOS1 desc