transpose a record in Oracle

Transpose a record in Oracle isn’t easy. I had a small table with several records and one value in a record. I wanted to transpose that table into one record with the values adjacent to each other. The question: how to accomplish this? Recently, Oracle introduced the pivot facility that allowed this procedure. The code to undertake is as follows:

select * from
    (select peri_omsch, 
        ROW_NUMBER ()  
        over (PARTITION BY een order by peri_omsch) as rn 
        from (select distinct '1' as een, peri_omsch from salesall order by peri_omsch))
          for rn in (1 as a1,2 as a2,3 as a3,4 as a4,5 as a5,6 as a6,7 as a7,8 as a8,9 as a9,10 as a10,11 as a11,12 as a12)

Let us start with this table:
The sql fetches the values from the original table (peri_omsch) and it adds an additional field that contains the row number. The code to add that additional field uses a ranking function where the whole table is seen as one set with a fixed value (‘een’) as an identifier for the set. Upon this set a rownumber is added.
We get


I use this rownumber to create the columns. Each value of the rownumber (1, 2, 3 etc ) is translated into a column. Hereby 1 is translated into column a1, 2 is translated into column a2 etc. I store the peri_omsch in this column. To enforce a unique value, I used the min function, which enforces one unique value to be stored.
The final result looks like: