problem in report with number and varchar2

hello,

I have several columns in a table with number datatype.for eg : select a||' '||b from tablename
However, when i concatenate some of the columns with number datatype
and use reports 6i, and when i click the properties of the field in the layout editor, the datatype is varchar2. why is this?

if i dont concatenate, then the property in layout editor for those are number.

what is the problem.

Thanks

Concatanation is a string operation. In order to concatanate numbers Oracle must convert them to varchar2's first. the result of the concatanation is therefore a varchar2. you can wrap the result in a to_number() function to convert it back again.

By the way, what data are you storing as numbers and concatanating? It sounds like there may be some bad design practice going on -- concatanation is not a "natural" operation to apply to numbers

Actually, I am doing a report which is hard to expain here, the report output for the accounts department is such that i have to do all tricks.they need the result side by side on a paper,comparitive result of this week to previous week.
select
to_char(GROSREV,'$99999,9999,999.99'))||''||to_char(GROSREV1,'$99999,9999,999.99')
if i do this, in the reportdesigner,the property is varchar2.

how do i convert this to number, so that in the reportdesigner,it is number only,so that i can play with formats inside the designer.

thanks

To do that, you would have to bring back the values individually, as numerics. It would probably be best to define the format as part of the select query, as you have done - you can't convert a series of number concatanated together with dollar signs and spaces back to a number.