SELECT fp.Physician_Key,
fp.Month,
pd.DisplayName,
hd.ProductName,
SUM(AmtPaid) AS TotalCost
FROM F_ProgramCost_Fact fp
INNER JOIN D_HEALTHPLANDim hd ON hd.HealthPlan_Key = fp.HealthPlan_Key
INNER JOIN D_PHYSICIANDim pd ON fp.Physician_Key = fp.Physician_Key
INNER JOIN F_MemberPatient_FactLess mpf ON fp.MemberPatientFact_Key = mpf.MemberPatientFact_Key
GROUP BY fp.Physician_Key
Getting this error "Column 'F_ProgramCost_Fact.Month' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause."
Please help! Thanks