SWQL Edit to Combine Rows into Singular Row

This should work, assuming it doesn't take too long to calculate.

SELECT 
g.DisplayName as Site
, Case
When n1.mm = 1 Then 'Jan'
When n1.mm = 2 Then 'Feb'
When n1.mm = 3 Then 'Mar'
When n1.mm = 4 Then 'Apr'
When n1.mm = 5 Then 'May'
When n1.mm = 6 Then 'Jun'
When n1.mm = 7 Then 'Jul'
When n1.mm = 8 Then 'Aug'
When n1.mm = 9 Then 'Sep'
When n1.mm = 10 Then 'Oct'
When n1.mm = 11 Then 'Nov'
When n1.mm = 12 Then 'Dec'
End as [1 Month Ago]
, n1.[Average Percent Availability] as [1 Month Ago Availability]
, Case
When n2.mm = 1 Then 'Jan'
When n2.mm = 2 Then 'Feb'
When n2.mm = 3 Then 'Mar'
When n2.mm = 4 Then 'Apr'
When n2.mm = 5 Then 'May'
When n2.mm = 6 Then 'Jun'
When n2.mm = 7 Then 'Jul'
When n2.mm = 8 Then 'Aug'
When n2.mm = 9 Then 'Sep'
When n2.mm = 10 Then 'Oct'
When n2.mm = 11 Then 'Nov'
When n2.mm = 12 Then 'Dec'
End as [2 Months Ago]
, n2.[Average Percent Availability] as [2 Months Ago Availability]
, Case
When n3.mm = 1 Then 'Jan'
When n3.mm = 2 Then 'Feb'
When n3.mm = 3 Then 'Mar'
When n3.mm = 4 Then 'Apr'
When n3.mm = 5 Then 'May'
When n3.mm = 6 Then 'Jun'
When n3.mm = 7 Then 'Jul'
When n3.mm = 8 Then 'Aug'
When n3.mm = 9 Then 'Sep'
When n3.mm = 10 Then 'Oct'
When n3.mm = 11 Then 'Nov'
When n3.mm = 12 Then 'Dec'
End as [3 Months Ago]
, n3.[Average Percent Availability] as [3 Months Ago Availability]

FROM orion.groups g
left join ( -- N-1
select cs.ContainerID, month(addmonth(-1,DATETRUNC('month',getdate()))) as mm, avg(cs.PercentAvailability) as [Average Percent Availability]
from orion.ContainerStatus cs
where cs.Container.CustomProperties.Business_Unit_Groups = 'X'
and cs.DateTime < DATETRUNC('month',getdate())
and cs.DateTime >= addmonth(-1,DATETRUNC('month',getdate()))
group by cs.ContainerID, month(cs.DateTime)
) n1 on n1.containerid=g.ContainerID

left join ( -- N-2
select cs.ContainerID,month(addmonth(-2,DATETRUNC('month',getdate()))) as mm, avg(cs.PercentAvailability) as [Average Percent Availability]
from orion.ContainerStatus cs
where cs.Container.CustomProperties.Business_Unit_Groups = 'X'
and cs.DateTime < addmonth(-1,DATETRUNC('month',getdate()))
and cs.DateTime >= addmonth(-2,DATETRUNC('month',getdate()))
group by cs.ContainerID, month(cs.DateTime)
) n2 on n2.containerid=g.ContainerID
left join ( -- N-3
select cs.ContainerID, month(addmonth(-3,DATETRUNC('month',getdate()))) as mm, avg(cs.PercentAvailability) as [Average Percent Availability]
from orion.ContainerStatus cs
where cs.Container.CustomProperties.Business_Unit_Groups = 'X'
and cs.DateTime < addmonth(-2,DATETRUNC('month',getdate()))
and cs.DateTime >= addmonth(-3,DATETRUNC('month',getdate()))
group by cs.ContainerID, month(cs.DateTime)
) n3 on n3.containerid=g.ContainerID

WHERE g.CustomProperties.Business_Unit_Groups = 'X'

This works great! Thank you! One small change I want to make is to pull the current month and then the previous two months like you have. What do I need to change to make that switch? 

This works great! Thank you! One small change I want to make is to pull the current month and then the previous two months like you have. What do I need to change to make that switch?