Make counter in sql query - php

Question

I am using codeigniter and have working query which take user 3 images. I want to make a count an give every image a number 1,2,3,4,5,6,7 ... and want that query output
-number (count),
-id,
-image,
-date
my sql query :
function bar_images_first($user_id)
{
$sql = "SELECT id, image, UNIX_TIMESTAMP(date) as date FROM images WHERE user_id = 3 LIMIT 3";
$query = $this->db->query($sql, $user_id);
return $query->result_array();
}
Is it possible to do counter in query?

Answer 1

It is possible by setting a SQL parameter as
SET #cnt := 0;
SELECT
#cnt := #cnt + 1,
id,
image,
UNIX_TIMESTAMP(date) as date
FROM images WHERE user_id = 3 LIMIT 3";
But such multiple statements cannot be executed from the PHP's mysql_query() method. But, mysqli function like mysqli_multi_query() does allow to execute multiple queries too, so if possible use mysqli method rather than the AR methods.
However, you can run multiple sets of query one by one.
$query = array(
"SET #cnt := 0;",
"SELECT
#cnt := #cnt + 1,
id,
image,
UNIX_TIMESTAMP(date) as date
FROM images WHERE user_id = 3 LIMIT 3"
);
foreach($query as $qry) {
$result= $this->db->query($qry);
//.........
}

Answer 2

To run as a single query:
SELECT #curRow := #curRow + 1 AS row_number, id, image, UNIX_TIMESTAMP(date) as date
FROM images
JOIN (SELECT #curRow := 0) r
WHERE user_id = 3
LIMIT 3
This is very specific to MySQL though. If you want more portable code I would recommend making your row counter in code instead.
Edit - forgot to give due credit: MySQL - row number in recordset?