Question

I’m working on a WordPress database, and I need some help cleaning up the post_content field.

There are about 5,000 posts that contain something like this:
RANDOM JUNK<img src="http://domain.tld/randomString.jpg" />MORE RANDOM JUNK

or

RANDOM JUNK<img src="http://domain.tld/randomString.png" />MORE RANDOM JUNK

or

RANDOM JUNK<img src="https://domain.tld/randomString.jpg" />MORE RANDOM JUNK

or

RANDOM JUNK<img src="https://domain.tld/randomString.png" />MORE RANDOM JUNK

I need to delete everything except the image, and there might be other HTML tags in some of the fields.

Where should a SQL beginner start?

Answer 1

It is not possible with sql. sql could just find a regexp and tell its there, but not capture a part of it and insert it again.

You need to query all images first then match your adresses then insert it again…

$sql = "SELECT postid, image FROM posts";
$result = mysql_query($sql) OR die(mysql_error());

while($row = mysql_fetch_assoc($result)) {
    preg_match('/<img[^>]+>/i', $row['image'], $matches);
    $sql = "UPDATE posts SET image = '".$matches[0]."'
            WHERE postid = ".$row['postid'];
    mysql_query($sq) OR die(mysql_error());
}