Re: Can we freeze the expression column and few rows in the table?
So you mean something like the freeze panes function in Excel. As you say, this already happens for dimensions in QV, and I don't know of any way to make an expression column freeze in the same way.
What you may be able to do, is to build a calculated dimension that contains the expression. That expression will then be in the "frozen" part of the chart. You will have to be careful not to affect the chart row construction, probably the best bet is to use an Aggr function like this:
=Aggr(your expression, Dim1, Dim2, Dim3....)
Where Dim1, 2, 3 etc are the existing chart dimensions. I have not tested this, but I believe that it should work.
Hope that helps
Logic will get you from a to b. Imagination will take you everywhere. - A Einstein