sql查询不会通过不寻常的字符来提取数据

I am using a mysqli query to pull data through:

$query = "SELECT * FROM prices WHERE item IN " . $inString;
$data = mysqli_query($mysqli, $query);
while($row = mysqli_fetch_array($data)) 
{
    $itemssql[$z] = array('name'=>$row['item'], 'price'=>$row['current_price']);
    $z++;
}

I have checked the query within phpMyAdmin and the correct rows are being pulled through however the while loop is disregarding certain rows.

e.g. a row where ['item'] = '★ Bayonet'

I believe it is to do with the character '★' as other rows with the following characters are not being pulled through: '龍王', '™'

What can I do to pull these rows through and add them to the array $itemssql?