Mysqli function causes database connection to fail

Asked Oct 31 '19 at 13:10

Active Oct 31 '19 at 13:15

Viewed 29 times

I have a function as follows:

function display_results() {
    $query = "SELECT *
            FROM comments WHERE id = 1";
    $result = mysqli_query($connection, $query);
    confirm_query($result);

    while ($row = mysqli_fetch_array($result)) {
        echo $row['comment'];
    }
}

In another file I include the function, and then call it:

<?php require_once($root . 'includes/ui_functions'); ?>
<?php display_results(); ?>

But it returns as "Database query failed", without any other information. This only happens since I switched from mysql_* to mysqli_* connection. The MySQL syntax is fine, it simply fails the database query no matter what I query it.

edited Oct 31 '19 at 13:15

asked Oct 31 '19 at 13:10

user1228907

From first glance this looks like it may be a [variable scope](https://www.php.net/manual/en/language.variables.scope.php) issue. Can we see how you define your `$connection` – IsThisJavascript Oct 31 '19 at 13:14
– user1228907 Oct 31 '19 at 13:16
I should add that all other database connections work fine IF they are done on the same page that's on the screen – user1228907 Oct 31 '19 at 13:16
I think you should try using `$GLOBALS['connection']` instead of `$connection` in your `mysqli_query` call – IsThisJavascript Oct 31 '19 at 13:18
Done, but didn't resolve the issue :( – user1228907 Oct 31 '19 at 13:22
Did you check the error logs, maybe they are more descriptive on why a connection cannot be made. – IsThisJavascript Oct 31 '19 at 13:25
1

You can always try dumping whatever your connection variable is inside that function to see if it is a scoping issue – IsThisJavascript Oct 31 '19 at 13:26
How do I check error log? – user1228907 Oct 31 '19 at 13:30
Ah yes, it was a scoping issue. When I put the mysqli_connect constants into the query it works. How do I go about fixing this? – user1228907 Oct 31 '19 at 13:33
1

Nevermind, I believe I've discovered the issue – user1228907 Oct 31 '19 at 13:34
One solution would be to directly pass the connection to the function. – IsThisJavascript Oct 31 '19 at 13:34
and you can find where your error logs are stored by viewing your php_info() – IsThisJavascript Oct 31 '19 at 13:35

Mysqli function causes database connection to fail

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