demo, MySQL - rextester

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drop table if exists your_table;

create table your_table (
	ID int,
	OrderID int,
	ProductID int,
	OrderDate date,
	Quantity int
	);
	
insert into your_table values
(1,1,1,'2017-01-01',1),
(2,1,1,'2017-01-01',6),
(3,1,1,'2017-01-03',9),
(4,1,1,'2017-01-04',3),
(5,1,1,'2017-01-05',5),
(6,1,1,'2017-01-07',1),
(7,1,1,'2017-01-09',2);

select d.date, coalesce(sum(t.quantity), 0) as quantity
from (
    select min_orderdate + INTERVAL (a.a + (10 * b.a) + (100 * c.a)) DAY as date
    from (
		select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9
		) as a
    cross join (
		select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9
		) as b
    cross join (
		select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9
		) as c
    join (
		select min(orderdate) min_orderdate, max(orderdate) max_orderdate from your_table
		) t on min_orderdate + INTERVAL (a.a + (10 * b.a) + (100 * c.a)) DAY <= max_orderdate
    ) d
left join your_table t on d.date = t.orderdate
group by d.date;


absolute service time: 0,43 sec