OpenCart 🇺🇦

$sql = "SELECT COUNT(DISTINCT customer_id) AS total FROM `" . DB_PREFIX . "customer_transaction`";

$implode = array();

if (!empty($data['filter_date_start'])) {
	$implode[] = "DATE(cr.date_added) >= '" . $this->db->escape($data['filter_date_start']) . "'";
}

if (!empty($data['filter_date_end'])) {
	$implode[] = "DATE(cr.date_added) <= '" . $this->db->escape($data['filter_date_end']) . "'";
}

if ($implode) {
	$sql .= " WHERE " . implode(" AND ", $implode);
}
		
if (isset($data['start']) || isset($data['limit'])) {
	if ($data['start'] < 0) {
		$data['start'] = 0;
	}			

	if ($data['limit'] < 1) {
		$data['limit'] = 20;
	}	
	
	$sql .= " LIMIT " . (int)$data['start'] . "," . (int)$data['limit'];
}
				
$query = $this->db->query($sql);

return $query->row['total'];