if i understand you well!
SELECT DISTINCTROW Format$([My_TBL].[My_date], 'mmmm yyyy') AS [date By Month], Sum([My_TBL].[money]) AS [total numbers of customers paying]
FROM My_TBL
GROUP BY Year([My_TBL].[My_date])*12 + DatePart('m',[My_TBL].[My_date]) -1, Format$([My_TBL].[My_date], 'mmmm...