Java 如何一次获取数据

我使用以下查询来获取使用jdbc的postgresql中一天的数据

  int[] days={1,2,3,4,5,6,9,12,18,24}

for(i=0;i<days.length;i++){
  //connect to database
    String sql="select id,extract ('day' from time) as day,count(*) as count from public.data where time>='2016-10-'"+days[i]+'06:00:00' and  time<='2016-10-"+days[i]+" 09:00:00' group by id,day ";
  //execute sql and close connection
}

像这样，它将给予每一天。 但是这是每天都要做的，我正在将结果集作为csv来编写。取而代之的是，我可以得到整个结果集，其中包含6到9个周期内的每天计数，而不是执行许多sql语句吗？但是我希望所有的结果集都是这样的

id    day      count
___   ___      _____
 1     1         10
 2     1         12
 3     1         8
 1     2         10
 2     2         9
 3     2         18
 1     3         10
 2     3         12
 3     3         27

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非常感谢您提供的任何帮助

您可以使用多功能一体使用过滤器，其中提取时间（day from time）在：天内，提取时间（hour from time）在6到8之间

---

：天用于hibernate查询中的参数映射，您可以使用sql的等效项。

首先您的查询有问题：

日期应介于两个

'

之间，而不是

'

：

您的查询应如下所示：

String sql="select id,extract ('day' from time) as day,count(*) as count 
            from public.data where time>='2016-10-"+days[i]+" 06:00:00' 
            and  time<='2016-10-"+days[i]+" 09:00:00' group by id,day ";

String sql=“选择id，从时间中提取（'day'作为日期，计数（*）作为计数
来自public.data，其中时间>='2016-10-“+天[i]+“06:00:00”
时间您可以在一条语句中执行此操作，无需循环：

select id,
       extract(day from time) as day,
       count(*) as count 
from public.data 
where extract(day from time) = any (array[1,2,3,4,5,6,9,12,18,24] ) 
  and time::date between date '2016-10-01' and date '2016-10-31'
  and time::time between time '06:00:00' and time '09:00:00'
group by id,day 


我希望
time
不是该列的真实名称
您永远不必使用批处理。
String sql="select id,extract ('day' from time) as day,count(*) as count 
            from public.data where time>='2016-10-"+days[i]+" 06:00:00' 
            and  time<='2016-10-"+days[i]+" 09:00:00' group by id,day ";

select id,
       extract(day from time) as day,
       count(*) as count 
from public.data 
where extract(day from time) = any (array[1,2,3,4,5,6,9,12,18,24] ) 
  and time::date between date '2016-10-01' and date '2016-10-31'
  and time::time between time '06:00:00' and time '09:00:00'
group by id,day