There are a few ways that you can perform this data transformation. You have access to the PIVOT
function then that will be the easiest, but if not then you can use an aggregate function and a CASE
.
Aggregate /Case version:
select personid,
max(case when optionid = 'A' then 1 else 0 end) OptionA,
max(case when optionid = 'B' then 1 else 0 end) OptionB,
max(case when optionid = 'C' then 1 else 0 end) OptionC
from PersonOptions
group by personid
order by personid;
See SQL Fiddle with Demo
Static Pivot:
select *
from
(
select personid, optionid
from PersonOptions
) src
pivot
(
count(optionid)
for optionid in ('A' as OptionA, 'B' OptionB, 'C' OptionC)
) piv
order by personid
See SQL Fiddle with Demo
Dynamic Version:
The two versions above work great if you have a known number of values, but if your values are unknown, then you will want to implement dynamic sql and in Oracle you can use a procedure:
CREATE OR REPLACE procedure dynamic_pivot_po(p_cursor in out sys_refcursor)
as
sql_query varchar2(1000) := 'select personid ';
begin
for x in (select distinct OptionID from PersonOptions order by 1)
loop
sql_query := sql_query ||
' , min(case when OptionID = '''||x.OptionID||''' then 1 else null end) as Option_'||x.OptionID;
dbms_output.put_line(sql_query);
end loop;
sql_query := sql_query || ' from PersonOptions group by personid order by personid';
dbms_output.put_line(sql_query);
open p_cursor for sql_query;
end;
/
Then you return the results, you will use:
variable x refcursor
exec dynamic_pivot_po(:x)
print x
The results are the same with all versions:
| PERSONID | OPTIONA | OPTIONB | OPTIONC |
------------------------------------------
| 1 | 1 | 1 | 0 |
| 2 | 0 | 0 | 1 |
| 3 | 0 | 1 | 0 |
| 4 | 1 | 0 | 1 |