If you want to beautify your number column inside an APEX report with a percent-sign then most of you would do like this:
select column_name || '%' as column_name
This creates the correct output but the sort will not work anymore as expected because a type conversion will automatically be applied. It is not longer a number column and the sort will be assigned as it would be a character column.
Luckily there is a easy workaround for this.
Let the select as it is:
And add this under the "Column Attributes">"Columns Formatting">"HTML Expression":
You might want to do the same with an Interactive Report then this trick could help you: http://cntrint.blogspot.com.au/2012/05/interactive-report-column-custom.html