Question

I have Database table of Questions. I use the integer variable Id to sort all the elements of the table.

What do I want?
Whenever, a new question is added. It is assigned a new id, which is 1 greated than the ID of the last question in my database.

Here is what I do:

include('dbconnect.php');



    $ids = $connection->prepare('SELECT * FROM question ORDER BY id ASC');
    $ids->execute(array());
    $result = $ids->fetchAll(PDO::FETCH_ASSOC);
    $new_id = end($result['id']); //Error in this line.
    $new_id = $new_id + 1;

But, I always get the error

Warning: end() expects parameter 1 to be array, null given in /Applications/MAMP/htdocs/question/submit.php on line 20

I am using the FetchAll statement so I feel, that an array should be returned. Can anyone figure out where is the error.

Each New Question, which is added to the database gets an ID of 1.

Answer 1

As documented under Using AUTO_INCREMENT:

The AUTO_INCREMENT attribute can be used to generate a unique identity for new rows:

CREATE TABLE animals (
     id MEDIUMINT NOT NULL AUTO_INCREMENT,
     name CHAR(30) NOT NULL,
     PRIMARY KEY (id)
);

INSERT INTO animals (name) VALUES
    ('dog'),('cat'),('penguin'),
    ('lax'),('whale'),('ostrich');

SELECT * FROM animals;

Which returns:

+----+---------+
| id | name    |
+----+---------+
|  1 | dog     |
|  2 | cat     |
|  3 | penguin |
|  4 | lax     |
|  5 | whale   |
|  6 | ostrich |
+----+---------+

No value was specified for the AUTO_INCREMENT column, so MySQL assigned sequence numbers automatically. You can also explicitly assign NULL or 0 to the column to generate sequence numbers.