oracle how to transpose columns into rows without UNION

Question

Assume, i have 4 columns in a table

id | col1 | col2 | col3 

now i want to transpose that into one column but in 4 rows:

resul         


        

Answer 1

This can be done using unpivot.

select result 
from tablename
unpivot (result for colnames in (id,col1,col2,col3))