Oracle 23c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
CREATE TYPE string_list AS TABLE OF VARCHAR2(4000);
CREATE OR REPLACE FUNCTION split_String(
  i_str    IN  CLOB,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN string_list DETERMINISTIC PIPELINED
AS
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      PIPE ROW (SUBSTR( i_str, p_start, p_end - p_start ));
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      PIPE ROW (SUBSTR( i_str, p_start, c_len - p_start + 1 ));
    END IF;
  END IF;
EXCEPTION
  WHEN NO_DATA_NEEDED THEN
    NULL;
END;
/
SELECT column_value
FROM   TABLE(split_string('abc , xyz', ' , ') );


COLUMN_VALUE


abc

xyz