select 
  (select count(*) from clients where homebase_since is not NULL) as instance_count,
  (select count(*) from clients where homebase_since is not NULL and server_id=:server_id:) as server_count,
  (select count(*) from clients where homebase_since is not NULL and server_id=:server_id: and client_id=:client_id:) as client_count;