即使所有其他行数据保持相同，MySQL UPDATE TIMESTAMP仍在行UPDATE上? [英] MySQL UPDATE TIMESTAMP on row UPDATE, even when all other row data remains the same?

问题描述

我有一个带有时间戳的表.

I have a table with a timestamp.

时间戳记设置为"ON UPDATE CURRENT_TIMESTAMP".

当我用与该行中已有数据相同的数据对行进行更新时，我仍然希望更新TIMESTAMP.它不是.为什么不呢?如果数据不同，则更新就可以了.

When I run an update on a row with data that is the same as the data already in that row, I still want the TIMESTAMP to update. It does not. Why does it not? If the data is different it updates just fine.

我意识到我可以强制使用TIMESTAMP = now()进行更新，但是我试图了解MySQL在做什么.

I realize I can force an update with TIMESTAMP = now(), but I am trying to understand what MySQL is doing.

推荐答案

您已经说过ON UPDATE.

如果所有行的值都相同，则不会发生更新.

There is no update happening if all the row's values are the same.

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