FIND Special Characters Oracle

 CREATE OR REPLACE TYPE WWT.WWT_XXWMS_CHAR_LIST_NRR IS TABLE OF CHAR(1 CHAR);

WITH wc
AS (SELECT inventory_item_id, segment2
FROM   mtl_system_items_b
WHERE  inventory_item_id IN (18736091,18736071,18791648,18689552,12492301,18695455
,616432,7304252,212663)
AND    organization_id = 101
)
 SELECT  t.inventory_item_id,
        CAST( c.COLUMN_VALUE AS CHAR(1 CHAR) ) AS character,
        COUNT(1) AS frequency
FROM    wc t,
        TABLE(
          CAST(
            MULTISET(
              SELECT SUBSTR( t.segment2, LEVEL, 1 )
              FROM   DUAL
              WHERE  REGEXP_LIKE( SUBSTR( t.segment2, LEVEL, 1 ), '[^a-zA-Z0-9]' )
              CONNECT BY LEVEL <= LENGTH( t.segment2 )
            ) AS WWT.WWT_XXWMS_CHAR_LIST_NRR
          )
        ) c
GROUP BY t.inventory_item_id, c.COLUMN_VALUE
/

WITH msib_wc
AS (SELECT  segment2
FROM   mtl_system_items_b
WHERE  inventory_item_id IN (18736091,18736071,18791648,18689552,12492301,18695455)
AND    organization_id = 101
)
SELECT  CAST( c.COLUMN_VALUE AS CHAR(1 CHAR) ) AS character,
        COUNT(1) AS frequency
FROM    msib_wc  ,
        TABLE(
          CAST(
            MULTISET(
              SELECT SUBSTR( msib_wc.segment2, LEVEL, 1 )
              FROM   DUAL
              WHERE  REGEXP_LIKE( SUBSTR( msib_wc.segment2, LEVEL, 1 ), '[^a-zA-Z0-9]' )
              CONNECT BY LEVEL <= LENGTH( msib_wc.segment2 )
            ) AS WWT.WWT_XXWMS_CHAR_LIST_NRR
          )
        ) c
GROUP BY c.COLUMN_VALUE
/