Convert SSIS packages to Snowflake SQL

<!-- Package: Order_ETL.dtsx -->
<!-- Data Flow Task: Load Orders -->

OLE DB Source: [dbo].[STG_ORDERS]
  SELECT OrderID, CustomerID, Amount,
         OrderDate, Status
  FROM STG_ORDERS
  WHERE Status IN ('NEW','UPDATED')

Derived Column: [OrderTier]
  (DT_WSTR,10)(
    Amount > 10000 ? "Enterprise" :
    Amount > 1000  ? "Business" :
    "Standard"
  )

Lookup: [DIM_CUSTOMERS]
  JOIN ON CustomerID = CustID
  OUTPUT: CustomerName, Segment

OLE DB Destination: [dbo].[FACT_ORDERS]
  INSERT INTO FACT_ORDERS
  (OrderID, CustomerName, Segment,
   OrderTier, Amount, OrderDate)

-- SSIS Data Flow → Snowflake SQL

-- Stream captures incremental changes
CREATE OR REPLACE STREAM stg_orders_stream
  ON TABLE stg_orders;

-- MERGE replaces full Data Flow pipeline
MERGE INTO fact_orders tgt
USING (
  SELECT
    s.OrderID,
    c.CustomerName,
    c.Segment,
    CASE
      WHEN s.Amount > 10000 THEN 'Enterprise'
      WHEN s.Amount > 1000  THEN 'Business'
      ELSE 'Standard'
    END AS OrderTier,
    s.Amount,
    s.OrderDate
  FROM stg_orders_stream s
  LEFT JOIN dim_customers c
    ON s.CustomerID = c.CustID
  WHERE s.Status IN ('NEW','UPDATED')
) src
ON tgt.OrderID = src.OrderID
WHEN MATCHED THEN UPDATE SET
  tgt.CustomerName = src.CustomerName,
  tgt.OrderTier    = src.OrderTier,
  tgt.Amount       = src.Amount
WHEN NOT MATCHED THEN INSERT VALUES (
  src.OrderID, src.CustomerName,
  src.Segment, src.OrderTier,
  src.Amount,  src.OrderDate
);

-- Task replaces SSIS scheduling
CREATE OR REPLACE TASK load_orders_task
  WAREHOUSE = ETL_WH
  SCHEDULE  = 'USING CRON 0 */2 * * * UTC'
  WHEN SYSTEM$STREAM_HAS_DATA('stg_orders_stream')
AS EXECUTE IMMEDIATE 'CALL sp_load_orders()';