Ilya78rus

UPDATE `trade_log` AS `tl`
  JOIN `users` AS `u` ON `tl`.`tradeId` = ? AND `tl`.`status` = 'send' 
    AND `u`.`steam_id` = `tl`.`steamid_other`
  SET `tl`.`status` = 'success', `u`.`balance` = `u`.`balance` + `tl`.`sum`

SELECT `steamid_other`, `sum` 
  FROM `trade_log` 
  WHERE `tradeId` = ? AND `status` = 'success'