Oracle Group and Pivot - Dynamic Pivot in Oracle - sql

Question

I have a table like this:
+-----+------+------------+
| SN | CASE | CASE_VALUE |
+-----+------+------------+
| A | AA | 1 |
| A | AB | 5 |
| A | AC | 3 |
| A | AD | 4 |
| B | BA | 5 |
| B | BB | 7 |
| B | BC | 5 |
| B | BD | 1 |
+-----+------+------------+
Not sure if there is any way to get
+-----+--------+--------------+--------+--------------+--------+--------------+--------+--------------+
| SN | CASE_1 | CASE_1_VALUE | CASE_2 | CASE_2_VALUE | CASE_3 | CASE_3_VALUE | CASE_4 | CASE_4_VALUE |
+-----+--------+--------------+--------+--------------+--------+--------------+--------+--------------+
| A | AA | 1 | AB | 5 | AC | 3 | AD | 4 |
| B | BA | 5 | BB | 7 | BC | 5 | BD | 1 |
+-----+--------+--------------+--------+--------------+--------+--------------+--------+--------------+
There is no order required for those four cases
28/02/2021 Edit
If there's no order between case name?
Like blow
+-----+------+------------+
| SN | CASE | CASE_VALUE |
+-----+------+------------+
| A | AB | 1 |
| A | CD | 5 |
| A | IJ | 3 |
| A | GH | 4 |
| B | OP | 5 |
| B | EF | 7 |
| B | MN | 5 |
| B | KJ | 1 |
+-----+------+------------+

Answer 1

One option is using conditional aggregation in order to pivot as desired such as
SELECT sn,
MAX(CASE WHEN SUBSTR(case,2,1) = 'A' THEN case END) AS case_1,
MAX(CASE WHEN SUBSTR(case,2,1) = 'A' THEN case_value END) AS case_1_value,
MAX(CASE WHEN SUBSTR(case,2,1) = 'B' THEN case END) AS case_2,
MAX(CASE WHEN SUBSTR(case,2,1) = 'B' THEN case_value END) AS case_2_value,
MAX(CASE WHEN SUBSTR(case,2,1) = 'C' THEN case END) AS case_3,
MAX(CASE WHEN SUBSTR(case,2,1) = 'C' THEN case_value END) AS case_3_value,
MAX(CASE WHEN SUBSTR(case,2,1) = 'D' THEN case END) AS case_4,
MAX(CASE WHEN SUBSTR(case,2,1) = 'D' THEN case_value END) AS case_4_value
FROM t
GROUP BY sn
Demo
The pivot is static in the above case. You can create a function returning of SYS_REFCURSOR type as below one in order to have a dynamic pivot
CREATE OR REPLACE FUNCTION Get_Pivoted_Cols RETURN SYS_REFCURSOR IS
v_recordset SYS_REFCURSOR;
v_sql VARCHAR2(32767);
v_cols VARCHAR2(32767);
BEGIN
SELECT LISTAGG( 'MAX(CASE WHEN SUBSTR(case,2,1) = '''||cs||''' THEN case END ) AS "case_'||rn||'",
MAX(CASE WHEN SUBSTR(case,2,1) = '''||cs||''' THEN case_value END ) AS "case_'||rn||'_value"', ',')
WITHIN GROUP ( ORDER BY rn )
INTO v_cols
FROM ( SELECT DISTINCT SUBSTR(case,2,1) AS cs, ROW_NUMBER() OVER (PARTITION BY sn ORDER BY case) AS rn
FROM t );
v_sql :='SELECT sn,'|| v_cols ||' FROM t GROUP BY sn';
OPEN v_recordset FOR v_sql;
RETURN v_recordset;
END;
/
and call from SQL Developer's Command Line in order to see the result set
VAR rc REFCURSOR
EXEC :rc := Get_Pivoted_Cols;
PRINT rc

Answer 2

You need to pivot rows, then to use decode function to map your output like below. (I hope CASE is not the real name of your column).
with your_data (SN, "CASE", CASE_VALUE ) as (
select 'A', 'AA', 1 from dual union all
select 'A', 'AB', 5 from dual union all
select 'A', 'AC', 3 from dual union all
select 'A', 'AD', 4 from dual union all
select 'B', 'BA', 5 from dual union all
select 'B', 'BB', 7 from dual union all
select 'B', 'BC', 5 from dual union all
select 'B', 'BD', 1 from dual
)
select SN
, decode(SN, 'A', CASE_1, CASE_5)CASE_1
, decode(SN, 'A', CASE_1_VALUE, CASE_5_VALUE)CASE_1_VALUE
, decode(SN, 'A', CASE_2, CASE_6)CASE_2
, decode(SN, 'A', CASE_2_VALUE, CASE_6_VALUE)CASE_2_VALUE
, decode(SN, 'A', CASE_3, CASE_7)CASE_3
, decode(SN, 'A', CASE_3_VALUE, CASE_7_VALUE)CASE_3_VALUE
, decode(SN, 'A', CASE_4, CASE_8)CASE_4
, decode(SN, 'A', CASE_4_VALUE, CASE_8_VALUE)CASE_4_VALUE
from your_data t
pivot (
max(case_value) as value, max("CASE") FOR "CASE" in (
'AA' CASE_1
,'AB' CASE_2
,'AC' CASE_3
,'AD' CASE_4
,'BA' CASE_5
,'BB' CASE_6
,'BC' CASE_7
,'BD' CASE_8
)
)
;

Answer 3

Closest I could get, assuming (based on your data) that the first character in case will always match with sn we can pivot on that second character
select *
from (
select
data.*
, substr(case, 2, 1) case_t
from data
)
pivot (
max(case) type
, max(case_value) value
for case_t in (
'A' case_1
, 'B' case_2
, 'C' case_3
, 'D' case_4
)
)