Doubt in anonymous Block

Question

Hi,
if run the below anonymous Block,it shows ouput as NULL,
I want to display the column names from the cursor.
DECLARE
V_PK_COLS VARCHAR2(400);
P_COLUMN_NAME VARCHAR2(400) := 'CF_FEEDBACK_KEY,CF_CUSTOMER_KEY';
P_TABLE_NAME VARCHAR2(400) := 'T_ID_CMS_FEEDBACK_DETAILS';
CURSOR C_PK_COLS IS
SELECT UCC.COLUMN_NAME
FROM USER_CONS_COLUMNS UCC,USER_CONSTRAINTS UC
WHERE UCC.TABLE_NAME = P_TABLE_NAME
AND UC.CONSTRAINT_TYPE = 'P'
AND UCC.CONSTRAINT_NAME = UC.CONSTRAINT_NAME
AND UC.TABLE_NAME=UCC.TABLE_NAME
AND UCC.COLUMN_NAME IN (CHR(39)||REPLACE(P_COLUMN_NAME,',',''',''')||CHR(39))
--AND UCC.COLUMN_NAME IN(P_COLUMN_NAME)
ORDER BY UCC.POSITION;
BEGIN
OPEN C_PK_COLS;
FETCH C_PK_COLS INTO V_PK_COLS;
CLOSE C_PK_COLS;
DBMS_OUTPUT.PUT_LINE('OutPut :- ' || P_COLUMN_NAME);
END;
Regards,
Fame

Answer 1

Why not use a loop, in case the key consists of more than one column:
Try something like:
DECLARE
V_PK_COLS     VARCHAR2(400);
P_COLUMN_NAME VARCHAR2(400) := 'CF_FEEDBACK_KEY,CF_CUSTOMER_KEY';
P_TABLE_NAME  VARCHAR2(400) := 'T_ID_CMS_FEEDBACK_DETAILS';
BEGIN
for rec in (   SELECT UCC.COLUMN_NAME
                 FROM USER_CONS_COLUMNS UCC, USER_CONSTRAINTS UC
                WHERE UCC.TABLE_NAME = P_TABLE_NAME
                  AND UC.CONSTRAINT_TYPE = 'P'
                  AND UCC.CONSTRAINT_NAME = UC.CONSTRAINT_NAME
                  AND UC.TABLE_NAME = UCC.TABLE_NAME
                  AND UCC.COLUMN_NAME IN
                      (CHR(39) || REPLACE(P_COLUMN_NAME, ',', ''',''') || CHR(39))
               --AND UCC.COLUMN_NAME IN(P_COLUMN_NAME)
                ORDER BY UCC.POSITION )
  loop
      DBMS_OUTPUT.PUT_LINE('OutPut :- ' || rec.COLUMN_NAME);
  end loop;               
END;