SQL Help

Hello,

I already tried this same basic question with no response....  maybe I was too wordy.  So here it is simplified.... what's the best way to write this query?  I'm open to using stored procedures, but even then I don't know how I would conditionally populate a resultset (refcursor).  Notice that in the first three cases, the expression is the exact same, only the return value is different.  This seems inefficient....

 

select
  (case when column1 = column2 then column3 end) as alias1,
  (case when column1 = column2 then column4 end) as alias2,
  (case when column1 = column2 then column5 end) as alias3,
  (case when column6 = column7 then column8 end) as alias4
from
  mytable
;

Any ideas? 

Thanks!