Hi,
You can do something like :
select distinct(ts.size) from tbl_size ts
inner join (
Select Size,[Order] From (
Select 'S' Size, 0 [Order]
Union
Select 'L' Size, 1 [Order]
Union
Select 'X' Size, 2 [Order]
Union
Select 'XL' Size, 3 [Order]
)t ) Temp on Temp.Size=ts.Size
wHERE ts.LIST_ID=17 Order by Temp.Order