This is a simple query to calculate average cycle time per team project from Team Foundation Server data warehouse.

tfs_cycle_time.sql

Declare @from date;
Declare @initial_state nvarchar(256);
Declare @final_state nvarchar(256);

Set @from = DATEADD(year,-1,GETDATE());
Set @initial_state = 'Committed';
Set @final_state = 'Done';

With wi As (
  Select TeamProjectSK, System_Id, System_State, System_ChangedDate, System_WorkItemType
    From [Tfs_Warehouse].[dbo].[DimWorkItem]
    Where 
      System_WorkItemType in ('Bug', 'Product Backlog Item')
      and System_ChangedDate >= @from
      and System_State in (@initial_state, @final_state)
)
Select P.ProjectPath, C.[Cycle Time]
  From DimTeamProject P
  inner join (
    Select D.TeamProjectSK, Avg(D.Duration) [Cycle Time]
      From (
        Select w1.TeamProjectSK, w1.System_Id, DateDiff(day, w1.ChangedDate, w2.ChangedDate) as Duration
          From (
            Select TeamProjectSK, System_Id, Min(System_ChangedDate) ChangedDate
              From wi
              Group By TeamProjectSK, System_Id, System_State
              Having System_State=@initial_state
          ) w1
          inner join (
            Select TeamProjectSK, System_Id, Max(System_ChangedDate) ChangedDate
              From wi
              Group By TeamProjectSK, System_Id, System_State
              Having System_State=@final_state
          ) w2
          On w1.System_Id=w2.System_Id
    ) D
    Group By D.TeamProjectSK
  ) C
  On C.TeamProjectSK=P.ProjectNodeSK