开业后截止8/1日的实际营业天数，流水和实收
做时间差，用count函数统计一下就行了。
select count(0) as 营业天数,sum(流水) as 流水,sum(实收) as 实收 from (select convert(date,营业时间) as 日期,sum(流水) as 流水,sum(实收) as 实收 from table where 营业时间<'2021-8-1' group by convert(date,营业时间)) a
由于一天可能营业多次，所以，要先按天求下流水和实收的和，然后外边套个查询，求总流水总实收以及天数统计