How to get columns which have values greater than 0

Dear all,

I have following output in sql server 

But i only want the columns which has data > 0. as i m using these columns as aliases e.g. 

SUM(CASE SizeBreakupDetail.Size WHEN 'XS' THEN MBSizeDetail.Qty ELSE 0 END) 'XS',
SUM(CASE SizeBreakupDetail.Size WHEN 'S' THEN MBSizeDetail.Qty ELSE 0 END) 'S',
SUM(CASE SizeBreakupDetail.Size WHEN 'M' THEN MBSizeDetail.Qty ELSE 0 END) 'M',
SUM(CASE SizeBreakupDetail.Size WHEN 'L' THEN MBSizeDetail.Qty ELSE 0 END) 'L',
SUM(CASE SizeBreakupDetail.Size WHEN 'XL' THEN MBSizeDetail.Qty ELSE 0 END) 'XL',
SUM(CASE SizeBreakupDetail.Size WHEN '2XL' THEN MBSizeDetail.Qty ELSE 0 END) '2XL',
SUM(CASE SizeBreakupDetail.Size WHEN '3XL' THEN MBSizeDetail.Qty ELSE 0 END) '3XL',
SUM(CASE SizeBreakupDetail.Size WHEN '4XL' THEN MBSizeDetail.Qty ELSE 0 END) '4XL',
SUM(CASE SizeBreakupDetail.Size WHEN '5XL' THEN MBSizeDetail.Qty ELSE 0 END) '5XL',
SUM(CASE SizeBreakupDetail.Size WHEN '6XL' THEN MBSizeDetail.Qty ELSE 0 END) '6XL'

.. so how to apply where clause in alises columns names... so that i can only get the columns value greater than 0.

Please help.

Thanks in adv.