Oracle 21c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
CREATE FUNCTION total_count_prods(item IN VARCHAR2)
RETURN NUMBER
IS
BEGIN
  RETURN 123456;
END;
/
SELECT SUBSTR(total_apples, 1, 4) || '-' || SUBSTR(total_apples, 5)
FROM   (
  SELECT total_count_prods('apple') AS total_apples
  FROM   DUAL
);


SUBSTR(TOTAL_APPLES,1,4)||'-'||SUBSTR(TOTAL_APPLES,5)


1234-56


SELECT REGEXP_REPLACE(
         total_count_prods('apple'),
         '(\d{2})$',
         '-\1'
       )
FROM   DUAL;


REGEXP_REPLACE(TOTAL_COUNT_PRODS('APPLE'),'(\D{2})$','-\1')


1234-56


SELECT TO_CHAR(
         total_count_prods('apple')/100,
         'FM9999D99',
         'NLS_NUMERIC_CHARACTERS=-,'
       )
FROM   dual;


TO_CHAR(TOTAL_COUNT_PRODS('APPLE')/100,'FM9999D99','NLS_NUMERIC_CHARACTERS=-,')


1234-56