如何获得两个日期之间的小时数差异? [英] How can I get the difference in hours between two dates?

问题描述

我必须执行选择"，以返回数据库中日期类型的字段与当前日期(以小时为单位)之间的差.我该如何在oracle中做到这一点?

I have to do a "select" that returns the difference between a field of type date from the database and the current date in hours. How can I do this in oracle?

我尝试:

   select 24 * (to_date(sysdate, 'YYYY-MM-DD hh24:mi') 
         - to_date('2012-02-28 15:20', 'YYYY-MM-DD hh24:mi')) diff_hours 
   from dual;

但是那没用.

推荐答案

错误是因为SYSDATE已经是日期，所以无需使用TO_DATE()将其转换为日期.

The error is because SYSDATE is already a date, there's no need to use TO_DATE() to convert it to a date.

如果您不将其转换为日期:

If you don't convert it to a date:

select
    24 * (sysdate - to_date('2012-02-28 15:20', 'YYYY-MM-DD hh24:mi')) as diff_hours
from dual;

如果日期格式错误，则可以使用两个步骤，例如:

And if the formatting of the dates are wrong, you can possible use two steps like:

select
    24 * (to_date(to_char(sysdate, 'YYYY-MM-DD hh24:mi'), 'YYYY-MM-DD hh24:mi') - to_date('2012-02-28 15:20', 'YYYY-MM-DD hh24:mi')) as diff_hours
from dual;

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