您应该创建一个临时表来存储日期范围之间的所有日期范围

CREATE TEMPORARY TABLE IF NOT EXISTS AllDateRange engine=memory 
 SELECT DATE(cal.date) Date
 FROM ( 
  SELECT  ( case when  @prmToDate = @prmFromDate then @prmFromDate else

  SUBDATE( @prmFromDate, INTERVAL  (DATEDIFF(@prmToDate,@prmFromDate))  DAY) + INTERVAL xc DAY end ) AS Date 
  FROM ( 
        SELECT @xi:=@xi+1 as xc from 
        (SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) xc1, 
        (SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) xc2, 
        (SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) xc3, 
        (SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) xc4, 
        (SELECT @xi:=+1) xc0 
  ) xxc1 
   ) cal WHERE DATE( cal.date)  >=  DATE(@prmFromDate)  and DATE( cal.date) <= DATE(@prmToDate)    ;

然后把它和你的table连接起来。

SELECT   count(COALESCE(c.empresa, 0)) as num ,   date_format(a.Date,"%d/%m/%Y") as data from AllDateTimeRange a 
 left join cupons c  on a.Date=date_format(c.dataCupo,"%Y-%m-%d") 
 WHERE c.dataCupo between @prmFromDate AND @prmToDate  AND  c.proveidor!="VINCULADO" and c.empresa=1 
 group by date_format(c.dataCupo,"%Y-%m-%d");

类似地，为月份和年份创建临时表，然后与主表联接，如上所述，以便分别获得月份和年份所需的结果。

最简单的方法是使用日历表。这个表将有一个datetime列，您可以加入其中，它对于报告非常有用。下面是一个如何在mysql中创建一个的示例。
https://gist.github.com/bryhal/4129042
现在您已经有了日历表，可以加入它来查找某个日期范围内所有日期的计数。
全天示例：

select num, td.db_date
FROM 
time_dimension td 
left join 
   (SELECT ifnull(COUNT(*),0) as num , c.dataCupo as data
   FROM cupons c 
   WHERE c.dataCupo between "2017-02-02" AND "2018-05-04" AND 
      c.proveidor!="VINCULADO" and c.empresa=1
   group by c.dataCupo) t
on t.data  = td.db_date
WHERE td.db_date between "2017-02-02" AND "2018-05-04"

所有月份示例：

select 
    sum(t.num),
    CONCAT(month(td.db_date),"-",year(td.db_date))
FROM 
time_dimension td 
left join 
   (SELECT 
       ifnull(COUNT(*),0) as num , 
       c.dataCupo as data
   FROM cupons c 
   WHERE c.dataCupo between "2017-02-02" AND "2018-05-04" AND 
      c.proveidor!="VINCULADO" and c.empresa=1) t

on c.data = t.data 
WHERE td.db_date between "2017-02-02" AND "2018-05-04" 
group by CONCAT(month(td.db_date),"-",year(td.db_date))