Simple Unpivot

I came across the need for an UNPIVOT today that require fairly basic syntax, so this is me noting it for later. A single column unpivot, not multiple.

I had a discrete set of values in local variables that I wanted to use within a merge, so I selected them from dual. Here is a literal representations

SELECT 'SCOTT' login_id 
  ,'X' alpha, 'Y' beta
  ,10 catgy1
  ,20 catgy2
  ,30 catgy3
  ,40 catgy4
  ,50 catgy5
  ,60 catgy6
FROM dual
/

LOGIN A B     CATGY1     CATGY2     CATGY3     CATGY4     CATGY5     CATGY6
----- - - ---------- ---------- ---------- ---------- ---------- ----------
SCOTT X Y         10         20         30         40         50         60

 1 row selected

Trouble is, I needed the categories described as rows, not columns. So I wrapped the original query within an unpivot, commenting how the syntax represents the translation.

select login_id, alpha, beta, catgy, quota -- new columns
from ( -- existing query
  select 'SCOTT' login_id 
      ,'X' alpha, 'Y' beta      
      ,10 catgy1
      ,20 catgy2
      ,30 catgy3
      ,40 catgy4
      ,50 catgy5
      ,60 catgy6
  from dual
) -- end existing query
unpivot
(
quota -- new column: value
  for catgy in -- new column translating previously separate columns to discrete data
    ( -- and the column -> data translation listed here
     catgy1 as 'CATGY1' 
    ,catgy2 as 'CATGY2'
    ,catgy3 as 'CATGY3'
    ,catgy4 as 'CATGY4'
    ,catgy5 as 'CATGY5' 
    ,catgy6 as 'CATGY6'
    )
)
/

LOGIN A B CATGY       QUOTA
----- - - ------ ----------
SCOTT X Y CATGY1         10
SCOTT X Y CATGY2         20
SCOTT X Y CATGY3         30
SCOTT X Y CATGY4         40
SCOTT X Y CATGY5         50
SCOTT X Y CATGY6         60

 6 rows selected 

Relatively easy! Hope it helps one day.

You can see the results from these statements at livesql.oracle.com