Query fail with no error - php

Question

I have a database UTF8 encoded, because it contains arabic letters. I have a php file to select all values from a given table:
<?php header('Content-type: application/json; charset=utf-8');
$host = "localhost"; //Your database host server
$db = "kalimat"; //Your database name
$user = "root"; //Your database user
$pass = ""; //Your password
$connection = mysqli_connect($host, $user, $pass);
//Check to see if we can connect to the server
if(!$connection)
{
die("Database server connection failed.");
die(mysqli_error($db));
}
else
{
//Attempt to select the database
$dbconnect = mysqli_select_db($connection, $db);
//Check to see if we could select the database
if(!$dbconnect)
{
die("Unable to connect to the specified database!");
}
else
{
$auteur=utf8_decode(urldecode($_GET["artist"]));
//$auteur=utf8_decode($auteur);
$resultset = mysqli_query($connection,"SELECT * FROM $auteur");
if( $resultset )
{
$records = array();
//Loop through all our records and add them to our array
while($r = mysqli_fetch_assoc($resultset))
{
$records[] = $r;
}
$records = array_map(function($r) {
$r['artist'] = utf8_encode($r['artist']);
return $r;
}, $records);
//Output the data as JSON
echo json_encode($records);
}
else{
die("Error:".mysqli_error()); //Here is the error
}
}
}
?>
In output, I have "Error:" without any specification, so I can't know the source of the problem.
Any something strange in the php file?
Thank you for your help.

Answer 1

have you tried utf8mb4 ?
ALTER DATABASE database_name CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;
ALTER TABLE table_name CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
utf8mb4 is superset of utf8
Advice: database ,table names and columns you should make them in non utf8 characters.
EDIT:
to handle with utf8 characters you have to make all in utf8 such as:
your files , convert them to utf8 , all pages where you are using utf8 also that page where you geting the author fom.
database , tables , columns.
your editor where you write codes.
headers.
...

Answer 2

try putting the following lines just after the php tag starts and error will be displayed.
error_reporting(E_ERROR);
ini_set("display_errors",1);
hope this helps.

Answer 3

You are using mysqli, not mysql. So you have to use appropriate error function, and call it according to it's proper syntax.
Also, your idea on storing data in user-defined tables is wrong. You have to learn relational database basics first.