Perhaps this?

if exists(select 1 from tempdb.sys.objects where object_id = object_id('tempdb..#TempTable'))

DROP TABLE #TempTable;

CREATE TABLE #TempTable(

[Customer] VARCHAR(50) NOT NULL,

[Status] INT NULL,

[CreatedDate] DATETIME NULL,

[LastUpdateDate] DATETIME NULL,

)

INSERT INTO #TempTable

SELECT 'CustA',1,'01/01/2013','01/01/2013'

UNION

SELECT 'CustA',2,'01/01/2013','01/05/2013'

UNION

SELECT 'CustA',1,'01/01/2013','01/20/2013'

UNION

SELECT 'CustA',3,'01/01/2013','02/01/2013'

UNION

SELECT 'CustB',1,'01/01/2013','01/01/2013'

UNION

SELECT 'CustC',2,'01/01/2013','01/05/2013'

UNION

SELECT 'CustB',1,'01/01/2013','01/20/2013'

UNION

SELECT 'CustB',3,'01/01/2013','02/01/2013';

go

with BaseData as (

select

Customer,

Status,

CreatedDate,

LastUpdateDate,

rn = row_number() over (partition by Customer order by LastUpdateDate)

from

#TempTable

)

select

bd1.Customer,

bd1.Status,

NumOfDays = sum(datediff(dd,bd1.LastUpdateDate,isnull(bd2.LastUpdateDate, getdate())))

from

BaseData bd1

left outer join BaseData bd2

on (bd1.Customer = bd2.Customer and

bd1.rn = bd2.rn - 1)

group by

bd1.Customer,

bd1.Status

order by

bd1.Customer,

bd1.Status;

go

if exists(select 1 from tempdb.sys.objects where object_id = object_id('tempdb..#TempTable'))

DROP TABLE #TempTable;

go