How would I bulk change posting date? I want to change about 20 post publish dates at a time in one click
Post date/time can't be changed via the Quick-Edit bulk editor. You might edit the SQL directly, if you're comfortable running a query in PHPMyAdmin. Or, you could search for a Plugin?
I just had a similar issue. I used this:
UPDATE `wp_posts` SET post_date = "2008-02-13 23:50:30" WHERE post_status = "publish" AND post_date >=DATE_SUB(CURDATE(),Interval 5 day)
It is updating the
wp_posts table and changing anything published in the last 5 days to the date of 2008-02-13.