Someone

CREATE VIEW taxation_aggregated AS
  SELECT DATE_FORMAT(taxation.call_start,'%Y-%m-%d')              AS call_date,
 	taxation.source_peer_name                                 AS customer,
         peer_to_company.company_name                             AS provider,
	 number_to_dest.tariffdesc                                AS destination,
	 sum(taxation.duration)/60                                AS volume,
	 sum(taxation.sell_eur) + 0.76 * sum(taxation.sell_usd)
   	 - sum(taxation.cost_eur) + 0.76 * sum(taxation.cost_usd) AS margin
    FROM taxation, number_to_dest, peer_to_company
   WHERE taxation.called_number = number_to_dest.called_number AND
         taxation.gateway_name = peer_to_company.gateway_name
GROUP BY call_date, customer, provider, destination