Last 3 Months Query

Hi,

I need to count last 3 months records. The query I'm trying to use was based on last 8 days. How can I use this query in months and not days? Or should I use a new query?




Code Snippet
SELECT COUNT(Column1) AS [Nº de Cartões], Column2 AS [Tipo de Cartão], Column4 AS Periodicidade
FROM main_client_file
WHERE (Column9 >= DATEADD(Day, DATEDIFF(Day, 0, GETDATE() - 3), 0)) AND (Column9 <= DATEADD(Day, DATEDIFF(Day, 0, GETDATE() - 1), 0))
GROUP BY Column2, Column4





Thx.