PostgreSQL：如何计算PostgreSQL中的DATE差异？(PostgreSQL: How to calculate DATE Difference in PostgreSQL?)

PostgreSQL：如何计算PostgreSQL中的DATE差异？(PostgreSQL: How to calculate DATE Difference in PostgreSQL?)

这里我需要计算PostgreSQL中两个日期的差异。

在SQL Server中 ：就像我们在SQL Server中执行操作一样简单。

DATEDIFF(Day, MIN(joindate), MAX(joindate)) AS DateDifference;

我的尝试 ：我正在尝试使用以下脚本：

(Max(joindate) - Min(joindate)) as DateDifference;

问题 ：

我的方法是正确的吗？

PostgreSQL中有没有函数来计算这个值？

Here I need to calculate the difference of the two dates in the PostgreSQL.

In SQL Server: Like we do in SQL Server its much easier.

DATEDIFF(Day, MIN(joindate), MAX(joindate)) AS DateDifference;

My Try: I am trying using the following script:

(Max(joindate) - Min(joindate)) as DateDifference;

Question:

Is my method is correct?

Is there any function in PostgreSQL to calculate this?

最满意答案

您的计算对于DATE类型是正确的，但是如果您的值是时间戳，则应该使用EXTRACT （或DATE_PART）确保只获取完整日期的差异;

EXTRACT(DAY FROM MAX(joindate)-MIN(joindate)) AS DateDifference

用于测试的SQLfiddle 。 请注意，时间戳差异比整整两天少1秒。

Your calculation is correct for DATE types, but if your values are timestamps, you should probably use EXTRACT (or DATE_PART) to be sure to get only the difference in full days;

EXTRACT(DAY FROM MAX(joindate)-MIN(joindate)) AS DateDifference

An SQLfiddle to test with. Note the timestamp difference being 1 second less than 2 full days.