CREATE FUNCTION funGetOstatok(schet_id INT)
RETURNS DOUBLE
BEGIN
DECLARE summa_ostatok double;
set summa_ostatok=(SELECT ostatok FROM q_ostatki_scheta WHERE kodOplati=schet_id);
RETURN IFNULL(summa_ostatok,0) ;
END

CREATE TABLE t_sales (
  sale_id int NOT NULL AUTO_INCREMENT,
  sale_number varchar(255) NOT NULL DEFAULT '',
  sale_date date DEFAULT NULL,
  sale_prihod double DEFAULT 0,
  sale_spisano double DEFAULT 0,
  dogovor_id int DEFAULT NULL,
  PRIMARY KEY (sale_id)
)

SELECT
  `a`.`sale_id` AS `sale_id`,
  (SUM(IFNULL((`b`.`sale_prihod` - `b`.`sale_spisano`), 0)) + MAX((`a`.`sale_prihod` - `a`.`sale_spisano`))) AS `ostatok`
FROM (`t_sales` `a`
  LEFT JOIN `t_sales` `b`
    ON (((`b`.`sale_id` < `a`.`sale_id`)
    AND (`b`.`sale_date` <= `a`.`sale_date`)
    AND (`b`.`dogovor_id` = `a`.`dogovor_id`))))
GROUP BY `a`.`sale_id`,
         `a`.`sale_date`

CREATE FUNCTION funGetOstatok(schet_id INT)
  RETURNS DOUBLE
BEGIN
DECLARE summa_ostatok double;
set summa_ostatok=(SELECT ostatok FROM v_test_ostatok WHERE sale_id=schet_id);
RETURN IFNULL(summa_ostatok,0) ;
END

SELECT
  `t_sales`.`sale_id` AS `sale_id`,
  `t_sales`.`sale_number` AS `sale_number`,
  `t_sales`.`sale_date` AS `sale_date`,
  `t_sales`.`sale_prihod` AS `sale_prihod`,
  `t_sales`.`sale_spisano` AS `sale_spisano`,
  `t_sales`.`dogovor_id` AS `dogovor_id`,
  `funGetOstatok`(`t_sales`.`sale_id`) AS `ostatok_obshiy`
FROM `t_sales`

SELECT
  `a`.`sale_id` AS `sale_id`,
  `a`.`sale_number` AS `sale_number`,
  `a`.`sale_date` AS `sala_date`,
  `a`.`sale_prihod` AS `sale_prihod`,
  `a`.`sale_spisano` AS `sale_spisano`,
  IFNULL((`a`.`sale_prihod` - `a`.`sale_spisano`), 0) AS `raznica`,
  (SUM(IFNULL((`b`.`sale_prihod` - `b`.`sale_spisano`), 0)) + MAX((`a`.`sale_prihod` - `a`.`sale_spisano`))) AS `ostatok`
FROM (`t_sales` `a`
  LEFT JOIN `t_sales` `b`
    ON (((`b`.`sale_id` < `a`.`sale_id`)
    AND (`b`.`sale_date` <= `a`.`sale_date`)
    AND (`b`.`dogovor_id` = `a`.`dogovor_id`))))
GROUP BY `a`.`sale_id`,
         `a`.`sale_date`