How to do custom query in magento?

Question

I want to write a custom query in magento website.

I created a file test.php in my magento root folder & written a custom query

Answer 1

Try this:

$connection = Mage::getSingleton('core/resource')->getConnection('core_read');
$sql        = "Select * from catalog_product_flat_1";
$rows       = $connection->fetchAll($sql); //fetchRow($sql), fetchOne($sql),...
Zend_Debug::dump($rows);

In order to test, you can create sandbox.php file in root of your magento installation and paste the following code:

<?php
$mageFilename = 'app/Mage.php';
require_once $mageFilename;
Mage::setIsDeveloperMode(true);
ini_set('display_errors', 1);
umask(0);
Mage::app();
$connection = Mage::getSingleton('core/resource')->getConnection('core_read');
$sql        = "Select * from catalog_product_flat_1";
$rows       = $connection->fetchAll($sql); //fetchRow($sql), fetchOne($sql),...
Zend_Debug::dump($rows);

and call from url as:

http://your-magento-url/sandbox.php