select	[caseID]
	,X = case when X >= 4 then 1 else 0 end
	,Y = case when Y >= 3 then 1 else 0 end
	,Z = case when Z >= 2 then 1 else 0 end
from	(
	select [caseID]
		,[X] = sum(case when datediff(day, startDate, getdate()) <= 180 then 1 else 0 end)
		,[Y] = sum(case when datediff(day, startDate, getdate()) <= 90 then 1 else 0 end)
		,[Z] = sum(case when datediff(day, startDate, getdate()) <= 30 then 1 else 0 end)
	from	TableA
	group by [CaseID]
	) d

declare @tableA table (caseid char(1), actionid int, startDate datetime)
insert @tableA
select 'A', 23, '2/21/2007' union all
select 'A', 21, '2/8/2007' union all
select 'B', 22, '12/4/2007' union all
select 'B', 13, '10/12/2007' union all
select 'B', 17, '10/7/2007' union all
select 'C', 61, '7/6/2007' union all
select 'D', 33, '11/2/2007' union all
select 'D', 56, '10/22/2007' union all
select 'D', 26, '7/29/2007' union all
select 'E', 22, '6/21/2007' union all
select 'E', 58, '5/25/2007' union all
select 'E', 87, '4/8/2007' union all
select 'E', 29, '3/23/2007'

;with yak (caseid, actionid, startdate, rn) as
(
select caseid, actionid, startdate, row_number() over (partition by caseid order by startdate)
from @tableA
)
select a.caseid
       ,max(case when datediff(day, a.startdate, x.startdate) <= 180 then 1 else 0 end) as Z       
       ,max(case when datediff(day, a.startdate, y.startdate) <= 90 then 1 else 0 end) as Z       
       ,max(case when datediff(day, a.startdate, z.startdate) <= 30 then 1 else 0 end) as Z
from yak a
left join yak z on a.caseid = z.caseid and z.rn = a.rn+1
left join yak y on a.caseid = y.caseid and y.rn = a.rn+2
left join yak x on a.caseid = x.caseid and x.rn = a.rn+3
group by a.caseid

output:
caseid Z           Z           Z
------ ----------- ----------- -----------
A      0           0           1
B      0           1           1
C      0           0           0
D      0           0           1
E      1           1           1