Magento 2: How to convert query in Magento format

Question

I have below query. How to convert it in to Magento format?

SELECT GROUP_CONCAT(id) as ids FROM table
WHERE YEAR(created_at) = YEAR(CURRENT_DATE - INTERVAL 1 MONTH)
AND MONTH(created_at) = MONTH(CURRENT_DATE - INTERVAL 1 MONTH)

Answer 1

Try following :

$resource = $this->_objectManager->create('\Magento\Framework\App\ResourceConnection');
$connection = $resource->getConnection(\Magento\Framework\App\ResourceConnection::DEFAULT_CONNECTION);
$sql = $connection->select()
    ->from('table_name', array('ids' => new \Zend_Db_Expr('GROUP_CONCAT(id)')))
    ->where('YEAR(created_at) = YEAR(CURRENT_DATE - INTERVAL 1 MONTH)')
    ->where('MONTH(created_at) = MONTH(CURRENT_DATE - INTERVAL 1 MONTH)');

$data = $connection->fetchAll($sql);
print_r($data);