问警告: mysql_fetch_assoc()要求参数%1为资源，给定字符串

EN

foreach($cat1 as $category){
    $query="SELECT parent FROM categories where id=".$category;
    $result = mysql_query($query);

    // Check result
    // This shows the actual query sent to MySQL, and the error. Useful for debugging.
    if (!$result) {
        $message  = 'Invalid query: ' . mysql_error() . "\n";
        $message .= 'Whole query: ' . $query;
        die($message);
    }

    if(mysql_num_rows($result) > 0) {
        $line = mysql_fetch_assoc($result);
        array_push($cat1,$line['parent']);
    }
    else {
       // do something else
    }
}

SELECT parent FROM categories where id=3