For example, I want collection list in order "sku2,sku3,sku1", but it list as "sku1,sku2", because the id of sku1 is smallernot simple DESC or ASC order. How to achieve it?
Example codes is below:
$skus = 'sku2,sku3,sku1';
$collection->addAttributeToSelect('*')
->addAttributeToFilter(
'sku', array('in' => $skus)
);
Magento 1.x has a way here How to specify custom sort order for product collection?, but it doesn't work on Magento 2:
$collection->getSelect()->order(new Zend_Db_Expr("FIELD(e.sku, $skus)"));
Fatal error: Uncaught Error: Class '.../Zend_Db_Expr' not found in ...