вы можете использовать конвертирование для контроля над форматом
SELECT
CONVERT(VARCHAR, YEAR(COALESCE(release_date, requested_date)))
+ RIGHT('00' + CONVERT(VARCHAR,
MONTH(COALESCE(release_date, requested_date))),2) as yrmnth
,salesrep
,customer_name
, Convert(decimal(12,2),
SUM(price_per_ea * COALESCE(open_release_qty, open_order_qty))) as ext_price