数据库中的数组错误

Question

I've got an array of usernames that needs to be matched with a db table upon post.

When I post it, I get the following error:

Warning: mysqli_fetch_row() expects parameter 1 to be mysqli_result, boolean given in /hermes/waloraweb008/b2049/information/folder/page.php on line 43 post_ok|213

This creates the array after the @sign (Works fine.):

$data = preg_replace('!((@)([-a-zA-Zа-яА-Я()0-9@:%_+.~#?&;//=]+))!i', '<a href="user.php?u=$3">$1</a>', $data);
$mentions = preg_match_all('!((@)([-a-zA-Zа-яА-Я()0-9@:%_+.~#?&;//=]+))!i', $data, $matches);
foreach ($matches as $findnames)
    {
        $shiz = implode(',',$findnames);
    }

This is what I want to check for the array within the db.

$mentionsql = "SELECT * FROM users WHERE username IN '$shiz'";
$mentionquery = mysqli_query($db_conx, $mentionsql);
$row83 = mysqli_fetch_row($mentionquery);
$musername = $row83["username"];

So that I can later do this:

mysqli_query($db_conx, "INSERT INTO notifications(username, initiator, app, which_status,did_read, date_time) 
                        VALUES('$musername','$log_username','<a href=user.php?u=$log_username>$log_username</a> mentioned you in a status.','$statusid',now(),now())");

Any ideas as to why there is an error?

Answer 1

As far as I can interpret your code $shiz is a comma-separated string of usernames, so: $shiz == 'user1, user2, user3'

on this line you are generating your query:

$mentionsql = "SELECT * FROM users WHERE username IN '$shiz'";

if you insert my example of $shiz you get a query like this:

"SELECT * FROM users WHERE username IN 'user1, user2, user3'"

However, the actual syntax for the SQL command In requires round brackets. Furthermore, if the usernames are strings, you need to put them in single quotes. So your query should look like this:

"SELECT * FROM users WHERE username IN ('user1', 'user2', 'user3')"