日期范围之间的时间戳

Question

我正在尝试使用查询查找每天的所有记录数：

select cast(Timestamp_field as date), count(*) as cnt
from table1 
group by 1 
having cast(Timestamp_field as date) between date and date -10;

Timestamp_field是一个时间戳，我将其转换为迄今为止。 这个; 尽管 Timestamp_field 的最大值显示为2016-09-20 12:31:38.000000 ，但不返回任何记录。 知道为什么吗？

Answer 1

我的猜测是问题出between . 也许这对你有用：

select cast(Timestamp_field as date), count(*)
from table1
group by 1
having cast(Timestamp_field as date) between date - 10 and date;

较小的值应该首先用于比较之间。

注意：您应该在group by之前进行过滤，而不是之后：

select cast(Timestamp_field as date), count(*)
from table1
where cast(Timestamp_field as date) between date - 10 and date;
group by 1