Hi, Friends.
I was trying to randomize the date of my wordpress posts that i imported from my other websites. I was curious that there will be a plugin to do this job quickly. And YES! i found one plugin that can may be do my job.

I installed that plugin and tired with it. They developed it nicely but not for the Bigger Numbers Of The Posts In List.
the plugin and site stopped working when i try to do such big operations, let’s say 1M rows.

Then i tried with PHPMYADMIN in the server and that’s done the job very smoothly.
Here is the query that i used to randomize the post.

UPDATE wt_posts SET post_date= FROM_UNIXTIME(
        UNIX_TIMESTAMP('2018-04-30 14:53:27') + FLOOR(0 + (RAND() * 63072000))
    ) WHERE 1;

I started from the Year 2018 You can set any year you want to start with.
I hope it may useful for you if you need to randomize the posts dates in batch.