Using sum in select statement without GROUP by

Question

select
   Col1,
   Col1/sum(Col1) as Fraction
from MyTable

This one will not return the desired result. If I add Gruop by Col1 then it will return a bunch of 1'a in the second column. How can I get around the problem?

Basically I want to treat the sum(Col1) as constant parameter. I can use with statement but I want a solution where I don't add another select statement.

I am using Toad and selecting from an Oracle database

Answer 1

Use SUM in its analytic form:

select
  col1,
  col1 / sum(col1) over () fraction
from mytable