I have a SQL which contains some group by with a count :

SELECT MAX(Program.Name) AS Program,MAX(Something.Name) AS Something,COUNT(*) AS 'Count of projects'
 FROM MainTable
 INNER JOIN Program ON MainTable.NoProgram=Program.ID
 INNER JOIN Something ON MainTable.NoSomething=Something.ID
 INNER JOIN Project ON MainTable.ID=Projet.NoMainTable
 GROUP BY Program.Name,Something.Name

Thus, I have my repartition on the first two fields followed by the count of projects corresponding to each record.

Now, I need to add another count. This one is based on the unique count of providers within the 'Count of projects'. Thus, if I have 17 projects, this may be within 5 providers.

I understand I may need to add a subquery somewhere to make that fit. Any suggestion on the best practice?