MS SQL Error Message

When I run this query I get an error message:

select Col1, Col2,
(convert(decimal(12,2),Col2)/convert(decimal(12,2),Col1))*100 as Col3
from (select top 100 percent count(col)as Col1,(select count(col)
from table where substring(col,6,2) > 49 and
substring(col,6,2) < 100) as Col2
from table
order by substring(col,1,4)
--group by col
) as mytable


Error message:
Server: Msg 8118, Level 16, State 1, Line 1
Column 'table.col' is invalid in the select list because it is not contained in an aggregate function and there is no GROUP BY clause.

I have tried adding the missing column everywhere and I am still getting this error message. I don't know what else to do. Please help.

let's look at your query, but first, let's re-write it so that it's somewhat easier to read --

now look at the nested query

you are returning the "top 100 percent" of what should be a single row, a row containing two numbers

therefore, to try to sort this single row by a substring makes no sense

I have tried to use order by without using top and I was getting this error message:

The ORDER BY clause is invalid in views, inline functions, derived tables, and subqueries, unless TOP is also specified.

Can you give me the work around? How else can I sort this query?

why do you want to sort one row??????