Funciones agregadas definidas por el usuario en Oracle PIVOT cláusula

Question

No se pueden usar las funciones agregadas definidas por el usuario en la cláusula Oracle PIVOT.

Creé una función agregada definida por el usuario llamada string_agg.
soy capaz de utilizarlo en una declaración simple, como ...

select id, string_agg(value) from 
(
    select 'user1' as id, 'BMW' as value, 'CAR'  as type from dual union 
    select 'user1' as id, 'Audi' as value, 'CAR'  as type from dual union 
    select 'user2' as id, 'Honda' as value, 'CAR'  as type from dual union 
    select 'user1' as id, 'Dell' as value, 'COMPUTER' as type from dual union 
    select 'user1' as id, 'Sony' as value, 'COMPUTER' as type from dual union 
    select 'user2' as id, 'HP' as value, 'COMPUTER' as type from dual 
) 
group by id, type

Resultados en:

ID TYPE STRING_AGG(VALUE) 
user1  CAR    Audi,BMW 
user1  COMPUTER  Dell,Sony 
user2  CAR    Honda 
user2  COMPUTER  HP 

Sin embargo cuando intento utilizar la misma función en una cláusula de pivote

select * from 
( 
    select id, type, string_agg(value) as value from 
    (
     select 'user1' as id, 'BMW' as value, 'CAR'  as type from dual union 
     select 'user1' as id, 'Audi' as value, 'CAR'  as type from dual union 
     select 'user2' as id, 'Honda' as value, 'CAR'  as type from dual union 
     select 'user1' as id, 'Dell' as value, 'COMPUTER' as type from dual union 
     select 'user1' as id, 'Sony' as value, 'COMPUTER' as type from dual union 
     select 'user2' as id, 'HP' as value, 'COMPUTER' as type from dual 
    ) 
    group by id, type 
) 
PIVOT (string_agg(value) FOR id IN ('user1' user1, 'user2' user2));

me sale el siguiente errores ...

ORA-56902: expect aggregate function inside pivot operation

esperado resultado es ...

TYPE USER1 USER2 
COMPUTER Dell,Sony HP  
CAR   Audi,BMW Honda

Answer 1

pivote no tiene que estar sobre la misma función agregada:

select * from 
( 
    select id, type, LISTAGG(value) WITHIN GROUP (ORDER BY 1) as value from 
    (
     select 'user1' as id, 'BMW' as value, 'CAR'  as type from dual union 
     select 'user1' as id, 'Audi' as value, 'CAR'  as type from dual union 
     select 'user2' as id, 'Honda' as value, 'CAR'  as type from dual union 
     select 'user1' as id, 'Dell' as value, 'COMPUTER' as type from dual union 
     select 'user1' as id, 'Sony' as value, 'COMPUTER' as type from dual union 
     select 'user2' as id, 'HP' as value, 'COMPUTER' as type from dual 
    ) 
    group by id, type 
) 
PIVOT (max(value) FOR id IN ('user1' user1, 'user2' user2)); 

Answer 2

¿Qué hay de tratar wmsys.wm_concat en lugar de su agregado definido por el usuario?