SELECT, format rows with different columns into a single row that share an ID - select

Question

I'm trying to format one SELECT statement so that it outputs a resultset with combined values over a few columns.
I have a resultset like this:
ID VID PID VALUE
1 x 1 a
2 y 1 A
3 y 2 B
4 x 2 b
5 y 3 C
6 x 3 c
7 x 4 d
8 y 4 D
9 x 5 e
10 y 5 E
Can I format one SELECT statement to effectively join the values with duplicate PIDs into a single row? I'm only really interested in PID and VALUE, e.g.
PID VALUE1 VALUE2
1 a A
2 b B
3 c C
4 d D
5 e E
Otherwise, should I be using actual JOINs with queries acting on the same table?
I tried to use CASE but can get up to a resultset like this:
ID VID PID VALUE1 VALUE2
1 x 1 a NULL
2 y 1 NULL A
3 y 2 NULL B
4 x 2 b NULL
5 y 3 NULL C
6 x 3 c NULL
7 x 4 d NULL
8 y 4 NULL D
9 x 5 e NULL
10 y 5 NULL E
The query I'm using looks somewhat like this.
SELECT
ID,
VID,
PID,
CASE WHEN VID = 'x' THEN VALUE END VALUE1,
CASE WHEN VID = 'y' THEN VALUE END VALUE2
FROM BIGTABLE
WHERE PID IN (1, 2, 3, 4, 5)
AND VID IN ('x', 'y')
There's a lot of values of PID and VID that aren't just 1-5 and x & y so I'm selecting them that way from the whole table.

Answer 1

Do you mean like this? It's called "conditional aggregation."
with
resultset ( id, vid, pid, value ) as (
select 1, 'x', 1, 'a' from dual union all
select 2, 'y', 1, 'A' from dual union all
select 3, 'y', 2, 'B' from dual union all
select 4, 'x', 2, 'b' from dual union all
select 5, 'y', 3, 'C' from dual union all
select 6, 'x', 3, 'c' from dual union all
select 7, 'x', 4, 'd' from dual union all
select 8, 'y', 4, 'D' from dual union all
select 9, 'x', 5, 'e' from dual union all
select 10, 'y', 5, 'E' from dual
)
-- End of simulated resultset (for testing purposes only, not part of the solution).
-- SQL query begins below this line.
select pid,
min(case when vid = 'x' then value end) as value1,
min(case when vid = 'y' then value end) as value2
from resultset
-- WHERE conditions, if any are needed - as in your attempt
group by pid
order by pid
;
PID VALUE1 VALUE2
--- ------ ------
1 a A
2 b B
3 c C
4 d D
5 e E