计算Oracle中两个时间戳之间的差异（以毫秒为单位） [英] Calculating difference between two timestamps in Oracle in milliseconds

问题描述

如何计算Oracle中两个时间戳之间的时间差（以毫秒为单位）？

How do I calculate the time difference in milliseconds between two timestamps in Oracle?

推荐答案

减去两个类型的变量 TIMESTAMP ，根据平台，您将获得 INTERVAL DAY TO SECOND ，其中包括数毫秒和/或微秒。如果数据库在Windows上运行，则 systimestamp 通常会有毫秒数。如果数据库在Unix上运行， systimestamp 通常会有微秒。

When you subtract two variables of type TIMESTAMP, you get an INTERVAL DAY TO SECOND which includes a number of milliseconds and/or microseconds depending on the platform. If the database is running on Windows, systimestamp will generally have milliseconds. If the database is running on Unix, systimestamp will generally have microseconds.

  1  select systimestamp - to_timestamp( '2012-07-23', 'yyyy-mm-dd' )
  2*   from dual
SQL> /

SYSTIMESTAMP-TO_TIMESTAMP('2012-07-23','YYYY-MM-DD')
---------------------------------------------------------------------------
+000000000 14:51:04.339000000

你可以使用 EXTRACT 函数来提取 INTERVAL DAY TO SECOND

You can use the EXTRACT function to extract the individual elements of an INTERVAL DAY TO SECOND

SQL> ed
Wrote file afiedt.buf

  1  select extract( day from diff ) days,
  2         extract( hour from diff ) hours,
  3         extract( minute from diff ) minutes,
  4         extract( second from diff ) seconds
  5    from (select systimestamp - to_timestamp( '2012-07-23', 'yyyy-mm-dd' ) diff
  6*           from dual)
SQL> /

      DAYS      HOURS    MINUTES    SECONDS
---------- ---------- ---------- ----------
         0         14         55     37.936

然后，您可以将每个这些组件为毫秒，并将其添加到

You can then convert each of those components into milliseconds and add them up

SQL> ed
Wrote file afiedt.buf

  1  select extract( day from diff )*24*60*60*1000 +
  2         extract( hour from diff )*60*60*1000 +
  3         extract( minute from diff )*60*1000 +
  4         round(extract( second from diff )*1000) total_milliseconds
  5    from (select systimestamp - to_timestamp( '2012-07-23', 'yyyy-mm-dd' ) diff
  6*           from dual)
SQL> /

TOTAL_MILLISECONDS
------------------
          53831842

然而，通常情况下，将 INTERVAL DAY TO SECOND 表示更为有用，或者单独列数为小时，分钟，秒等，而不是计算两个 TIMESTAMP 值之间的总毫秒数。

Normally, however, it is more useful to have either the INTERVAL DAY TO SECOND representation or to have separate columns for hours, minutes, seconds, etc. rather than computing the total number of milliseconds between two TIMESTAMP values.

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