计算 MySQL 中两个日期时间之间的差异
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Calculate difference between two datetimes in MySQL
提问by Devesh Agrawal
I am storing the last login time in MySQL in, datetime-type filed. When users logs in, I want to get the difference between the last login time and the current time (which I get using NOW()).
我将上次登录时间存储在 MySQL 中，datetime-type 归档。当用户登录时，我想获得上次登录时间和当前时间（我使用的时间NOW()）之间的差异。
How can I calculate it?
我该如何计算？
回答by FSP
USE TIMESTAMPDIFFMySQL function. For example, you can use:
使用TIMESTAMPDIFFMySQL 函数。例如，您可以使用：
SELECT TIMESTAMPDIFF(SECOND, '2012-06-06 13:13:55', '2012-06-06 15:20:18')
In your case, the third parameter of TIMSTAMPDIFFfunction would be the current login time (NOW()). Second parameter would be the last login time, which is already in the database.
在您的情况下，TIMSTAMPDIFF函数的第三个参数将是当前登录时间 ( NOW())。第二个参数是上次登录时间，该时间已经在数据库中。
回答by ingconti
my two cents about logic:
我对逻辑的两分钱：
syntax is "old date" - :"new date", so:
语法是“旧日期” - :“新日期”，所以：
SELECT TIMESTAMPDIFF(SECOND, '2018-11-15 15:00:00', '2018-11-15 15:00:30')
gives 30,
给 30,
SELECT TIMESTAMPDIFF(SECOND, '2018-11-15 15:00:55', '2018-11-15 15:00:15')
gives: -40
给：-40
回答by Adi
If your start and end datetimes are on different days use TIMEDIFF.
如果您的开始和结束日期时间在不同的日子，请使用 TIMEDIFF。
SELECT TIMEDIFF(datetime1,datetime2)
if datetime1 > datetime2 then
如果 datetime1 > datetime2 那么
SELECT TIMEDIFF("2019-02-20 23:46:00","2019-02-19 23:45:00")
gives: 24:01:00
给： 24:01:00
and datetime1 < datetime2
和日期时间 1 < 日期时间 2
SELECT TIMEDIFF("2019-02-19 23:45:00","2019-02-20 23:46:00")
gives: -24:01:00
给出：-24:01:00
