Firebird 3.0

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CREATE TABLE tb_orders(id INT,order_date DATE,price INT,customer_id INT)
INSERT INTO tb_orders
SELECT 1 id,  '01.01.2001' AS order_date, 100 AS price, 4583  AS customer_id from RDB$DATABASE
UNION ALL SELECT 2 ,'01.02.2001', 0, 4583   from RDB$DATABASE
UNION ALL SELECT 3 ,'20.02.2001', 0, 4583   from RDB$DATABASE
UNION ALL SELECT 4 ,'04.04.2001', 200, 4583  from RDB$DATABASE
4 rows affected

SELECT sub.*, MAX(price) OVER(PARTITION BY grp) AS somefield
FROM  (
    select a.id,order_date,
          coalesce(a.price,0) price,
          customer_id,
          sum(CASE WHEN price = 0 THEN 0 ELSE 1 END) OVER (order by a.order_date) grp
    from tb_orders a
    where a.customer_id=4583 
      --and a.orderstate = 1
) sub
order by order_date


ID
ORDER_DATE
PRICE
CUSTOMER_ID
GRP
SOMEFIELD


1
2001-01-01
100
4583
1
100

2
2001-02-01
0
4583
1
100

3
2001-02-20
0
4583
1
100

4
2001-04-04
200
4583
2
200

ID	ORDER_DATE	PRICE	CUSTOMER_ID	GRP	SOMEFIELD
1	2001-01-01	100	4583	1	100
2	2001-02-01	0	4583	1	100
3	2001-02-20	0	4583	1	100
4	2001-04-04	200	4583	2	200