Write SQL query to solve given problem: What is the difference in order number from "WARE-MKL1006" and "WARE-NBV1002"?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT SUM(IIF(WarehouseCode = 'WARE-MKL1006', 1, 0)) - SUM(IIF(WarehouseCode = 'WARE-NBV1002', 1, 0)) AS difference FROM `Sales Orders`