How to get specified value from DB? - php

Question

How can I get this value from DB as string or int?
PHPMyAdmin http://img200.imageshack.us/img200/6388/gr55.jpg
I've tried this:
$var = $this->db->query("SELECT SUBSTRING(`category_id`, 1, 3)
AS `category_id` FROM " . DB_PREFIX . "category
WHERE merlion_id = 'Q1'
ORDER BY category_id ASC");
And then I've checked it with var_dump and receive this:
var_dump($var);
object(stdClass)#26 (3) { ["row"]=> array(1) { ["category_id"]=> string(3) "859" } ["rows"]=> array(1) { [0]=> array(1) { ["category_id"]=> string(3) "859" } } ["num_rows"]=> int(1) }

Answer 1

No need to do SUBSTRING:
$var = $this->db->query("`category_id`FROM " . DB_PREFIX . "category
WHERE merlion_id = 'Q1'
ORDER BY category_id ASC");
Then, you have it, you don't "convert" the object, you take what you need from it:
$category_id = $var->row["category_id"];
I suggest you dive into basic PHP before you continue with your database-driven application. This is all trivial stuff. There are many good tutorials out there, also about PHP object oriented programming. Most notably the PHP documentation site.

Answer 2

How about this:
echo $var->row['category_id'];
You can also simplify your query:
$var = $this->db->query("SELECT `category_id`
AS `category_id` FROM `" . DB_PREFIX . "category`
WHERE merlion_id = 'Q1'
LIMIT 1");
Added backticks around the table name
Removed your ORDER clause. You do not need it if you only have one dataset whose *merlion_id* is Q1.
Added LIMIT clause since you only want one dataset.