create TABLE #Temporary_tbl
(
    ProductColour VARCHAR(50),
    ProductSize VARCHAR(20),
)

insert into #Temporary_tbl (ProductColour)
select distinct productcolour
from shoptransfer

insert into #Temporary_tbl (ProductSize)
select distinct ProductSize
from shoptransfer

select * from #Temporary_tbl

select distinct ProductColour, null as ProductSize
from shoptransfer

union all

select distinct null as ProductColor, ProductSize
from shoptransfer

SELECT DISTINCT
  CASE x.f WHEN 1 THEN s.ProductColour END AS ProductColour
  CASE x.f WHEN 2 THEN s.ProductSize   END AS ProductSize
FROM shoptransfer s
  CROSS JOIN (SELECT 1 UNION ALL SELECT 2) x (f)