MYSQLi w funkcji Opcje

[mskiba]

Witam, mam problem, jak w funkcji zastosuje zapytanie mysqli to wywala mi bald:

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Call to a member function query() on a non-object in
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Kod:

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function check_parts_price($fields_name,$id_parts)
{
	$sql = $connect_user_db->query("SELECT $fields_name FROM parts_price WHERE id_parts='".$id_parts."'");
	$check_parts_price = $sql->fetch_array(MYSQLI_ASSOC);
 
	return $check_parts_price[''.$fields_name.''];
}
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A zapytanie mysql dziala poprawnie:

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function check_parts_price($fields_name,$id_parts)
{
	$sql = mysql_query("SELECT $fields_name FROM parts_price WHERE id_parts='".$id_parts."'");
	$check_parts_price = mysql_fetch_array($sql);
 
	return $check_parts_price[''.$fields_name.''];
}
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