Priority search on columns
A simple OR condition will do this:

select * 
from dtsc_search_data
where c1 = 2
  or (c1 &lt;&gt; 2 and c2 = 2)
  or (c1 &lt;&gt; 2 and c2 &lt;&gt; 2 and c3 = 2);


SQLFiddle example: http://sqlfiddle.com/#!15/d1ca1/1