DATEDIFF（）参数问题

问题描述

旧的DATEDIFF（）允许用户使用3个参数，我试图这样做，所以我可以从我的DATEDIFF而不是几天中获得几个小时（我试图从一个帖子开始显示几个小时）。在我的数据库中，我使用一个TIMESTAMP和这行代码来拉一个值，显然它不起作用，因为我有额外的参数。一旦我删除'小时'或'hh'，查询就会运行，并返回一个以天为单位的值。

SELECT DATEDIFF（hour，CURDATE ，（SELECT Post_Date FROM Post_T WHERE pk_PostID = 1））

有一种简单的方法可以返回小时值吗？

另外我使用的是MYSQL版本5.5.20。

解决方案

就像在：

如果您希望在几个小时内使用结果，您应该使用

单位参数可以是： code> MICROSECOND（微秒），SECOND，MINUTE，HOUR，DAY，WEEK，MONTH，QUARTER或YEAR。

你可以这样做：

  SELECT TIMESTAMPDIFF（hour，CURDATE（），（SELECT Post_Date FROM Post_T WHERE pk_PostID = 1）） 
  

The old DATEDIFF() allowed users to use 3 parameters, and I was trying to do this so I could get hours out of my DATEDIFF rather than days, (I'm trying to show hours since a post). In my database I'm using a TIMESTAMP and this line of code to pull a value, and obviously it doesn't work because I have the extra parameter. Once I remove the 'hour' or 'hh' the query runs and returns a value in days.

SELECT DATEDIFF(hour, CURDATE(), (SELECT Post_Date FROM Post_T WHERE pk_PostID = 1) )

Is there an easy way I can return the hourly value?

Also I'm using MYSQL Version 5.5.20.

解决方案

Like it says in the documentation:

If you want the result in hours you should use Timestampdiff

The unit argument can be: MICROSECOND (microseconds), SECOND, MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER, or YEAR.

In your case you can do:

SELECT TIMESTAMPDIFF(hour, CURDATE(), (SELECT Post_Date FROM Post_T WHERE pk_PostID = 1) )

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