Magento – Magento search not returning results when keywords dont have space

It appears that the problem is when adding attributes to filter the Zend_DbAdapter quoteInto strips out the ?.

I would suggest using an sql wildcard for a single character _ instead of the ?. This will not match exactly ? but will instead match any single character. Note that this could return false results as the two urls that follow would both match:

http://localhost/magento/index.php/electronics/cameras.html?cat=25&price=-100
http://localhost/magento/index.php/electronics/cameras.html*cat=25&price=-100

Have a look at Alan Storm's answer for a bit more detail on the problem: https://stackoverflow.com/questions/3555932/magento-loadbyattribute-fails-on-question-marks

It might be because it's an empty collection. Without further testing I wouldn't know for sure. But maybe give this a try

public function prepareProductCollection($collection)
{
    $collection
        ->addAttributeToSelect('entity_id')
        ->addSearchFilter(Mage::helper('catalogsearch')->getQuery()->getQueryText())
        ->setStore(Mage::app()->getStore())
        ->addMinimalPrice()
        ->addFinalPrice()
        ->addTaxPercents()
        ->addStoreFilter()
        ->addUrlRewrite();


    $extra_collection = Mage::getResourceModel('catalog/product_collection')
                            ->addFieldToSelect('entity_id')
                            ->addFieldToFilter('entity_id', array(1,2));

    $collection_ids = array_merge($collection->getAllId(), $extra_collection);

    $collection = Mage::getResourceModel('catalog/product_collection')
                            ->addAttributeToSelect(Mage::getSingleton('catalog/config')->getProductAttributes())
                            ->addFieldToFilter('entity_id', $collection_ids);


    Mage::getSingleton('catalog/product_status')->addVisibleFilterToCollection($collection);
    Mage::getSingleton('catalog/product_visibility')->addVisibleInSearchFilterToCollection($collection);

    return $this;
}