yes. it simple and effective. 🙂

After follow your advice, this my query

SELECT t3.DATE_TAKEN,t3.MAIN_ID,t3.DAILY_RAINFALL,ltrf.month_year,

ltrf.cumrf1year

FROM

(SELECT CAST(CAST(m.Month AS varchar(2)) + '/1/' + CAST(m.Year AS varchar(4)) AS datetime) AS DATE_TAKEN,m.MAIN_ID,m.DAILY_RAINFALL

FROM

(

SELECT MONTH(t.Date_Taken) AS Month,

YEAR(t.Date_Taken)...

million thanks. it's work perfectly. :D. your explanation is awesome. 😉