SQL to SWQL - Report writer to web reports

I'm trying to migrate some of my reports into web report to have one report rather than a multitude.

I have a large custom report that looks for the average availability of last month per custom group. I can't get it to work in the SWQL and was wondering if anyone could help? If I can get this small section to work then I can edit the rest of the query.

SELECT TOP 10000 AVG(ResponseTime.Availability) AS AVERAGE_of_Availability,

       COUNT(DISTINCT Nodes.NodeID) AS COUNT_of_NodeID,

       'Campus-Core-Agg' AS AREA

FROM   Nodes INNER JOIN ResponseTime ON (Nodes.NodeID = ResponseTime.NodeID)

WHERE  ( DateTime between  (DATEADD(m, DATEDIFF(m, 0, getdate()) -1 , 0)) AND (DATEADD(m, DATEDIFF(m, 0, getdate()) , 0))

)

AND    (

            (Nodes.Vendor = 'Juniper Networks, Inc.')

       AND  (Nodes.Core_Aggregation = 1)

Many thanks!!!