Function defined in anonymous block?

Question

Quick question. I'd like to define a temporary function in a PL/SQL anonymous block. I'm thinking that I've seen an example of that done before, but I can't seem to find the example. Here's the source. Given a table name, I want to return a comma-delimited list of the columns in the table. As a stored function, this works like a charm:
CREATE OR REPLACE
FUNCTION columnlist_csv (in_tablename VARCHAR2) RETURN VARCHAR2 IS
v_columnlist VARCHAR2(4000);
v_num_columns NUMBER(4,0);
CURSOR c1(c1_tablename VARCHAR2) IS
SELECT column_name, column_id FROM user_tab_columns
WHERE table_name = c1_tablename ORDER BY column_id;
BEGIN
SELECT count(*) INTO v_num_columns FROM user_tab_columns WHERE table_name=in_tablename;
FOR c1row IN c1(in_tablename) LOOP
v_columnlist := v_columnlist||c1row.column_name;
IF c1row.column_id < v_num_columns THEN
v_columnlist := v_columnlist||', ';
END IF;
END LOOP;
RETURN v_columnlist;
END;
SELECT columnlist_csv(upper('&tablename')) FROM dual;
But, rather than having the function be a stored function, I'd prefer to define a temporary function on the fly in the script, like below. However, this doesn't work as an anonymous block. I believe I simply have the syntax wrong, and I'm hoping someone like lend a second pair of eyes...
DECLARE
FUNCTION columnlist_csv (in_tablename VARCHAR2) RETURN VARCHAR2 IS
v_columnlist VARCHAR2(4000);
v_num_columns NUMBER(4,0);
CURSOR c1(c1_tablename VARCHAR2) IS
SELECT column_name, column_id FROM user_tab_columns
WHERE table_name = c1_tablename ORDER BY column_id;
BEGIN
SELECT count(*) INTO v_num_columns FROM user_tab_columns WHERE table_name=in_tablename;
FOR c1row IN c1(in_tablename) LOOP
v_columnlist := v_columnlist||c1row.column_name;
IF c1row.column_id < v_num_columns THEN
v_columnlist := v_columnlist||', ';
END IF;
END LOOP;
RETURN v_columnlist;
END;
SELECT columnlist_csv(upper('&tablename')) FROM dual;
Can anyone advise?
Regards,
Dave

Answer 1

I want to return a comma-delimited list of the columns in the tableIf this is the goal, you could use a simple SELECT statement, SQL> desc test111;
Name                            Null?    Type
TRX_NUMBER                               VARCHAR2(20)
TRX_AMOUNT                               NUMBER(12,2)
SQL> select  decode(column_id,1,'',',') || lower(column_name) col_name
  2  from    user_tab_columns
  3  where   table_name = upper('&table_name')
  4  order by column_id
  5  /
Enter value for table_name: test111
old   3: where   table_name = upper('&table_name')
new   3: where   table_name = upper('test111')
COL_NAME
trx_number
,trx_amountThx,
SriDHAR