Сергей

SELECT DATE_ADD(date_from, INTERVAL rn DAY) AS `date`
FROM task
INNER JOIN (
  SELECT @rn := @rn + 1 AS rn
  FROM (
    SELECT *
    FROM (
      SELECT 1 AS n1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
      SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL 
      SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 
    ) AS t1 CROSS JOIN (
      SELECT 1 AS n2 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL 
      SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL 
      SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
    ) AS t2
  ) AS t CROSS JOIN (SELECT @rn := -1) AS var   
) AS tally ON DATEDIFF(date_to, date_from) >= rn
ORDER BY `date`