Remove spaces from sku from DB direct - Solution by Mr.Sandip Rathod

echo now();
echo "<br />";
$resource = Mage::getSingleton('core/resource');

/**
* Retrieve the read connection
*/
$readConnection = $resource->getConnection('core_read');
$writeConnection = $resource->getConnection('core_write');
$query01 = "SELECT entity_id, sku FROM catalog_product_entity";
$allsku =  $readConnection->fetchAll($query01);
$i = 0;
foreach($allsku as $item) {
if($item['sku'] != '') {
$sku =  trim((trim($item['sku'])), "<br />");
$sku = str_replace("<br />", "", $sku);
echo "'".$sku."'";
$entity_id = $item['entity_id'];
echo "<br />";
echo $i . " = ";
echo $query1 = "UPDATE `catalog_product_entity` SET `sku` = '$sku' WHERE `catalog_product_entity`.`entity_id` = $entity_id";
echo "<br />";echo "<br />";
$writeConnection->query($query1);
$i++;
}
}
echo "<br />";
echo now();
exit;