Editable ALV with dynamically growing columns

Hi Gurus,

I have one Parameter table and another data (transaction) table

When I fetch the data from data table I have put a when condition to one of date field in data table with between sy-datum and sy-datum + need to run days in parameter table

Its working properly

So my requirement is …. 

There are three key fields (fixed) and

when the parameter value = 4 ALV columns must be 7

when the parameter value = 6 ALV columns must be 9

like that.

So I want to know how can I do this?

My second question is when the ALV displaying, user need to change there value in ALV list, so therefore ALV should be editable.

Please help me o solve these problems.