Monthly transactions in a row-CodePudding

In SQL server, I want to achieve sum of transactions spent on a monthly basis for the past 6 months. Below is the query that I have written

with filter_6month_transactions as (
    SELECT 
        emplid, 
        format(transactiondate, 'yyyyMM') transactionmonth,
        expenseamountreimbursementcurrency,
        reimbursementcurrency,
        CAST(DATEADD(m, -6, GetDate()) AS date) report_start_date,
        DENSE_RANK() OVER(ORDER BY format(transactiondate, 'yyyyMM')) Rank,
        er.exchangerate
    FROM Concur_Expenses_CC_HighLimit_UDA e
     LEFT join exchange_rates er
     ON e.ReimbursementCurrency = er.FromCurrency
    WHERE paymenttype LIKE '