delete from m_transaction_cost where m_transaction_cost_id not in (
  select min(tc.m_transaction_cost_id)
  from m_transaction_cost tc
  group by tc.m_transaction_id, tc.ad_client_id, tc.ad_org_id, tc.isactive, tc.cost, tc.costdate, tc.c_currency_id, tc.dateacct
);