SQL：结合大小写和数字到日期的转换

Question

我想要做一个sql语句，它在一个表中计算两个日期值的减法。如果该值为负值，我只想将其显示为0值。

数字值是付款处于当前状态的秒数。 我把它与技巧转换为时间值（日期类型）。

我当前的代码是

SELECT 
max(CASE WHEN t1.time_event < SYSDATE and t2.time_event > SYSDATE THEN to_char(to_date(max(round(SYSDATE - t1.time_event) * 24 * 60 * 60)),'ssssss'),'hh24:mi:ss') else to_char(to_date(0)) END) as "current_age" 
from tbl_dummyfeed t1 join tbl_dummyfeed t2 on t1.payment_Id = t2.payment_id 
where t1.event = 'accepted' and t2.event = 'enriched'); 

Answer 1

您可以使用类似的日期'技巧'，即将小数天差额添加到名义日期（其中时间部分为午夜） - 您可以使用固定日期或trunc(sysdate)，只要时间最终成为午夜 - 不必乘以24 * 60 * 60。 （您的to_date()解决方案隐含地执行相同的操作，有效地将当前月份第一天的午夜秒数加上;但这可能会更清晰一些）。但你也可以移动case条款为where过滤

select to_char(date '1970-01-01' 
    + nvl(max(sysdate - t1.time_event), 0), 'HH24:MI:SS') as "current_age" 
from tbl_dummyfeed t1 
join tbl_dummyfeed t2 
on t1.trax_id = t2.trax_id 
where t1.event = 'accepted' 
and t1.time_event < sysdate 
and t2.event = 'enriched' 
and t2.time_event > sysdate; 

你也可以使用一个分析方法，所以你只需要打表一次，用一个子查询对了每个“富”的时间与以往“接受”时间该ID，并且您然后过滤针对当前时间：

select to_char(date '1970-01-01' 
    + nvl(max(sysdate - time_accepted), 0), 'HH24:MI:SS') as "current_age" 
from (
    select last_value(case when event = 'accepted' then time_event end ignore nulls) 
     over (partition by trax_id order by time_event) as time_accepted, 
    case when event = 'enriched' then time_event end as time_enriched 
    from tbl_dummyfeed 
) 
where time_accepted < sysdate 
and time_enriched > sysdate; 

Answer 2

这工作，只有转化为时间HH24：MI：SS仍然需要发生。

SELECT max(CASE WHEN t1.time_event < SYSDATE and t2.time_event > SYSDATE THEN round((SYSDATE - t1.time_event) * 24 * 60 * 60) else 0 END) as "current_age" 
    from tbl_dummyfeed t1 join tbl_dummyfeed t2 on t1.payment_id= t2.payment_id 
    where t1.event = 'accepted' and t2.event = 'enriched'; 

当我加入转换到HH24：MM：SS的解决方案看起来像这样

SELECT to_char(to_date(max(CASE WHEN t1.time_event < SYSDATE and t2.time_event > SYSDATE THEN round((SYSDATE - t1.time_event) * 24 * 60 
* 60) else 0 END),'sssss'),'hh24:mi:ss') as "current_age" from tbl_dummyfeed t1 join tbl_dummyfeed t2 on t1.trax_Id = t2.trax_id where t1.event = 'accepted' and t2.event = 'enriched'; 

这是我的问题的唯一的好办法。希望这可以帮助人们。