Cambiar separador de función WM_CONCAT de Oracle 11gR2

Es posible que desee utilizar LISTAGG .

SELECT col_id, 
       LISTAGG(col_text, '|') WITHIN GROUP (ORDER BY col_text) text
  FROM table1
 GROUP BY col_id

Salida:

| COL_ID |            TEXT |
----------------------------
|    111 | This|a|is|test. |

SQLFiddle

ACTUALIZAR Si necesita obtener valores de texto distintos en una lista

SELECT col_id, 
       LISTAGG(col_text, '|')
         WITHIN GROUP (ORDER BY col_text) text
  FROM 
(
  SELECT DISTINCT col_id, col_text
    FROM table1
)
 GROUP BY col_id

SQLFiddle