Question

我正在尝试将小时和小时与双重保存在我的表格中保存的实际数据中。

TO_CHAR（sysdate，'HH.MI'）返回char但我的数据包含浮点数

但它没有找到数据。

我正在尝试这样做：

 create or replace function getSysTime

   return char

  is
      hhhh             intervals.interval_end%type;
   v_interval_start    intervals.interval_start%type;
   v_interval_end     intervals.interval_end%type;
   v_interval_id    intervals.interval_id%type;

  begin

     select  INTERVAL_START ,INTERVAL_END , INTERVAL_ID , TO_CHAR(sysdate,'HH.MI')
     into  v_interval_start , v_interval_end , v_interval_id , hhhh
    from INTERVALS

    where hhhh  =  INTERVAL_START ;

    return v_interval_id;    

   end;

解决了：

 sloved by using cast char to float . 

  where cast (TO_CHAR(sysdate,'HH.MI') as float)  between  INTERVAL_START and INTERVAL_END ;

Answer 1

欢迎使用Stack Overflow！

您的WHERE子句通常用于将SELECT语句限制为满足WHERE条件的行（即WHERE myTable.favoriteNumber = 5）。或者，你可以在那里有一个布尔表达式。 WHERE 1=1评估为WHERE TRUE。因为它是TRUE，所以返回所有行。 WHERE 0=2对WHERE FALSE进行评估，因此不会返回任何行，因为0在任何行中都不等于2。

无论如何，从逻辑上考虑一下。为了获得一组行，您需要为其提供参数。数据库如何知道您想要哪些行？首先，您必须使用SELECT选择字段。哪张桌子？定义FROM。您想要符合特定条件的行子集吗？添加WHERE。我在哪里可以存储行中的值？添加INTO。仅仅因为PL / SQL是程序性的并不意味着你总是从上到下，从左到右阅读。

在知道哪些行符合hhhh条件之前，您的代码可能无法在WHERE中插入值。因此，您有WHERE null = INTERVAL_START。

如果此答案有助于回答您的问题，请选择左侧的“接受的答案”复选标记。

Answer 2

看起来你正在寻找这样的东西？

-- I'm lazy and provide only a few intervals
create table intervals as
select 1 as id, 8 +  0/60 as start_, 8 + 19/60 as end_, '8:00 - 8:19' as desc_ from dual union all
select 2 as id, 8 + 20/60 as start_, 8 + 39/60 as end_, '8:20 - 8:39' as desc_ from dual union all
select 3 as id, 8 + 40/60 as start_, 8 + 59/60 as end_, '8:40 - 8:59' as desc_ from dual union all
select 4 as id, 9 +  0/60 as start_, 9 + 19/60 as end_, '9:00 - 9:19' as desc_ from dual union all
select 5 as id, 9 + 20/60 as start_, 9 + 39/60 as end_, '9:20 - 9:39' as desc_ from dual union all
select 6 as id, 9 + 40/60 as start_, 9 + 59/60 as end_, '9:40 - 9:59' as desc_ from dual
;

示例查询：

select * from intervals 
where extract(hour from localtimestamp) + 
      (extract(minute from localtimestamp) / 60)
between start_ and end_;

select * from intervals
where extract(hour from to_timestamp('2013-08-29 08:39:59', 'YYYY-MM-DD HH24:MI:SS')) + 
      (extract(minute from to_timestamp('2013-08-29 08:39:59', 'YYYY-MM-DD HH24:MI:SS')) / 60)
between start_ and end_;

select * from intervals
where extract(hour from to_timestamp('2013-08-29 08:40:00', 'YYYY-MM-DD HH24:MI:SS')) + 
      (extract(minute from to_timestamp('2013-08-29 08:40:00', 'YYYY-MM-DD HH24:MI:SS')) / 60)
between start_ and end_;

访问间隔表的便捷功能：

create or replace function get_interval_id(
  p_time in timestamp default localtimestamp
) return number as
  v_id number;
begin
  select id into v_id
    from intervals
   where extract(hour from p_time) + 
         (extract(minute from p_time) / 60)
  between start_ and end_;

  return v_id;
exception
  when others then
    return null;
end;
/
show errors

如何使用该功能：

SQL> select localtimestamp from dual;

LOCALTIMESTAMP
---------------------------------------------------------------------------
2013-08-29 09:41:51.388

SQL> select * from intervals where id = get_interval_id;

        ID     START_       END_ DESC_
---------- ---------- ---------- -----------
         6 9.66666667 9.98333333 9:40 - 9:59

SQL> select * from intervals where id = get_interval_id(to_timestamp('2013-08-29 08:59:00', 'YYYY-MM-DD HH24:MI:SS'));

        ID     START_       END_ DESC_
---------- ---------- ---------- -----------
         3 8.66666667 8.98333333 8:40 - 8:59

将to_char与float进行比较

2 个答案: