如何在此MySql表的所有记录中更改此字段的值？

Question

I have the following situation.

In a MySql database I have a posts table. This table contains the following 2 fields: post_modified and post_date

For each record present in the posts table I need set the value of post_modified field with the value into the post_date

How can I do a query that do this work on all the table records?

Tnx

Answer 1

这很简单：

UPDATE posts SET post_modified = post_date;

Answer 2

此查询应完成以下工作：

UPDATE posts SET post_modified=post_date;

Answer 3

You would just use an update without a condition to update all records:

update posts set post_modified = post_date

Depending on the settings in the database an update without a condition might not be allowed. Then you would add a dummy condition just to tell the database that you actually want to change every record:

update posts set post_modified = post_date where 1 = 1