tab_to_string [Error] Execution (37: 13): ORA-06502: PL/SQL: numeric or value error: character string buffer too small

Question

I've found the tab_to_string from other Q/A for aggregation values. hope this can solve the problem but it seems something is not right.

CREATE OR REPLACE TYPE FMF_VERIFY5.t_varchar2_tab AS TABLE OF VARCHAR2(32767);

CREATE OR REPLACE FUNCTION FMF_tab_to_string (p_varchar2_tab  IN  t_varchar2_tab,
                                          p_delimiter     IN  VARCHAR2 DEFAULT ',') RETURN VARCHAR2 IS
  l_string     VARCHAR2(32767);
BEGIN
  FOR i IN p_varchar2_tab.FIRST .. p_varchar2_tab.LAST LOOP
    IF i != p_varchar2_tab.FIRST THEN
      l_string := l_string || p_delimiter;
    END IF;
    l_string := l_string || p_varchar2_tab(i);
  END LOOP;
  RETURN l_string;
END tab_to_string;
/

SELECT ID, tab_to_string(CAST(COLLECT(COMMENTS ORDER BY DATE DESC) AS t_varchar2_tab),'//') AS COMMENTS
FROM TABLE

Above SELECT query works time to time based on the input value. it looks like when comment has big data it throws an error.

COMMENT is varchar(1024) and there can be up to 20 comments.

Answer 1

You can try this query for getting a comment in clob and restrict the size to 32767.

SELECT
    LENGTH(LIST),
    LIST
FROM
    (
        SELECT
            SUBSTR(RTRIM(XMLAGG(XMLELEMENT(E, COMMENT, ',').EXTRACT('//text()')).GETCLOBVAL(), ','), 1, 32767) AS LIST
        FROM
            MYTABLE
    );

db<>fiddle demo

Cheers!!