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I am trying to do an average between different rows data as shown below.

Here's my original Questions
which McNets answered.

So basically here is the table

create table t (id int identity, BIDID int,  AppID int, AppStatus varchar(20), [Time] date);

insert into t values

(23390, 16, 'In Review', '20170307'), 

(23390, 16, 'Approved',  '20170309'), 

(23390, 16, 'In Review', '20171110'), 

(23390, 16, 'Approved',  '20171112'), 

(23390, 17, 'In Review',  '20171114'),

(23390, 18, 'Approved',  '20171112'), 

(23390, 16, 'Approved',  '20171114'),

(23391, 17, 'In Review',  '20171112'), 

(23391, 18, 'Approved',  '20171114')

I am trying to calculate the average between In Review and Approved values only first between an individual AppID and then doing the Average in different AppId's in a individual bid and then finally doing the Average between all the bids to come to a single number

Here is the code for it

SELECT

    CASE WHEN t1.AppStatus = 'In Review' AND t2.AppStatus = 'Approved'

         THEN DATEDIFF(day, t1.[Time], t2.[Time])

         ELSE 0

    END as Days

FROM

    t t1

CROSS APPLY(SELECT TOP 1 * 

            FROM t

            WHERE id > t1.id

            ORDER BY id) t2

and this gets me the Average

WITH ct AS

(

SELECT

    CASE WHEN t1.AppStatus = 'In Review' AND t2.AppStatus = 'Approved'

         THEN DATEDIFF(day, t1.[Time], t2.[Time])

         ELSE 0

    END as Days

FROM

    t t1

CROSS APPLY(SELECT TOP 1 * 

            FROM t

            WHERE id > t1.id

            ORDER BY id) t2

)

SELECT

    SUM(days) / COUNT(*) Average

FROM

    ct

WHERE

    days <> 0

This currently does not do any grouping of any sort so it just takes into account first In Review and then finds the next Approved and so on. I need to group it first by AppID to calculate individual AppId average and then do the average of different AppId's inside a bid and then do an average of the bid's

(23390, 16, 'In Review', '20170307'), 

(23390, 16, 'Approved',  '20170309'), 

(23390, 16, 'In Review', '20171110'), 

(23390, 16, 'Approved',  '20171112'), 

(23390, 17, 'In Review',  '20171114'),

(23390, 18, 'Approved',  '20171112'), 

(23390, 16, 'Approved',  '20171114'),

(23391, 17, 'In Review',  '20171112'), 

(23391, 18, 'Approved',  '20171114')

First group by BidID so 2 bids 23390 and 23391 then Avg with App Id 16,17 for first Bid and 18 for second bid and then calculate the Avg between the bids.

Can someone please tell me how should I add the grouping.

DBFiddle

Thanks