为什么我的UPDATE sql查询不起作用？ 不会更新表

Question

Is there something wrong with my function here? I've created a simple task manager with a blog page as well. This is the same function I use to update Tasks in the task table, just modified to update the Blog table instead.

function update_blog($blogpost) {
    global $db;

    $sql = "UPDATE Blog SET ";
    $sql .= "blog_date='" . db_escape($db, $blogpost['blog_date']) . "', ";
    $sql .= "blog_content='" . db_escape($db, 
    $blogpost['blog_content']) . "' ";
    $sql .= "WHERE id='" . db_escape($db, $blogpost['id']) . "' ";
    $sql .= "LIMIT 1";

    $result = mysqli_query($db, $sql);

    if($result) {
      return true;
    } else {
      // UPDATE failed
      echo mysqli_error($db);
      db_disconnect($db);
      exit;
    }
}

From edit.php , the user is redirected to blog.php upon submitting their blog post edits. However, the edits are not seen and the table itself is not updated. Am I missing something simple here?

Answer 1

It might have something to do with a record with db_escape($db, $blogpost['id']) not being present in the database (if the query is not failing). I would recommend executing a simple SELECT to see how many rows exist, eg:

SELECT * 
FROM Blog
WHERE id = <value of db_escape($db, $blogpost['id'])>;

If you don't get any rows, that probably means there is no record present and hence, no update. You might have to pass different value in that case, depending on what you have in the form.