create table table1
(productid varchar(10), price float, discount float, supplyid int)

insert table1
select '0001', 0.5, 0.02, 1
union all select '0001', 0.4, 0.03, 2
union all select '0001', 0.4, 0.01, 3
union all select '0002', 1, 0, 1
union all select '0002', 0.8, 0, 2
union all select '0002', 0.9, 0, 3
union all select '0003', 0.8, 0.02, 1
union all select '0003', 0.7, 0.01, 2
union all select '0003', 0.8, 0.03, 3

With cte 
AS
(select row_number() over (order by productid, discount) as rowid, productid, price, discount, supplyid 
 from table1)

select c.productid, c.price, c.discount, c.supplyid from cte c
JOIN 
(select productid, min(rowid) as rowid from cte
group by productid
)t 
ON c.productid = t.productid AND c.rowid = t.rowid