Oracle - select statement to pivot and change how data is displayed - oracle

Question

I currently have data in an Oracle tabel that looks like this:
Person_ID Fieldname Fieldnumber
123 2016 Salary 50000
123 2015 Salary 45000
123 2014 Salary 40000
123 2016 Vacation Days 5
456 2016 Salary 50000
456 2016 Vacation Days 5
789 2016 Salary 90000
789 2016 Vacation Days 5
I would like write a select statement to Pivot and change the display of the data so it looks like this:
Person_ID Fieldname 2016 2015 2014
123 Salary 55000 45000 40000
123 Vacation Days 5
456 Salary 50000
456 Vacation Days 5
789 Salary 90000
789 Salary 5
How can I do this so that if new field names are added, my SQL will automatically add new columns when I run it? Is there a way to do this with pivot or should I use union or another function that I am not familiar with?
The pivot I usually run looks like this but I don't think the concept will work in this scenario:
select *
from cust_matrix
unpivot
(
state_counts
for state_code in ("New York","Conn","New Jersey","Florida","Missouri")
)
order by "Puchase Frequency", state_code
Thank you

Answer 1

Don't be confused by the fact that there are two columns that are not part of the "pivot", in your case person_id and fieldname. Pivoting works exactly the same way.
Notes - your input table is obviously missing a column name (for year) - which better not be Year, a reserved word in Oracle. I used yr in my sample inputs. You also have a typo in the output (where did 55000 come from, for year 2016 and person_id = 123? The inputs had 50000).
And, you can have 2016 as a column name, but it would have to be double-quoted and it may cause unexpected problems later. Best to use standard column names - which, in particular, can't begin with a digit. I used y2016 etc.
with
inputs ( person_id, yr, fieldname, fieldnumber ) as (
select 123, 2016, 'Salary' , 50000 from dual union all
select 123, 2015, 'Salary' , 45000 from dual union all
select 123, 2014, 'Salary' , 40000 from dual union all
select 123, 2016, 'Vacation Days', 5 from dual union all
select 456, 2016, 'Salary' , 50000 from dual union all
select 456, 2016, 'Vacation Days', 5 from dual union all
select 789, 2016, 'Salary' , 90000 from dual union all
select 789, 2016, 'Vacation Days', 5 from dual
)
-- end of test data; actual solution (SQL query) begins below this line
select person_id, fieldname, y2016, y2015, y2014
from inputs
pivot ( max(fieldnumber) for yr in (2016 as y2016, 2015 as y2015, 2014 as y2014) )
order by person_id, fieldname
;
PERSON_ID FIELDNAME Y2016 Y2015 Y2014
--------- ------------- ----- ----- -----
123 Salary 50000 45000 40000
123 Vacation Days 5
456 Salary 50000
456 Vacation Days 5
789 Salary 90000
789 Vacation Days 5