How to extract value inside with statement? - oracle

Question

I want to initialize variable in pl/sql In the following way. But the value of the variable is null. how can I modify this code?
CREATE OR REPLACE PROCEDURE P_TEMP
(
pList0 OUT SYS_REFCURSOR
)
AS
TEMP_COL1 VARCHAR2(100);
TEMP_COL2 VARCHAR2(100);
BEGIN
OPEN cv_1 FOR
WITH TEMP_TABLE(COLUMN_1, COLUMN_2 ,...., COLUMN_N)
AS (SELECT COL_1, COL_2, ... , COL_N)
SELECT COL_1, COL_2
INTO TEMP_COL1, TEMP_COL2
FROM TEMP_TABLE;
DBMS_OUTPUT.PUT_LINE(TEMP_COL1); -- null!!
DBMS_OUTPUT.PUT_LINE(TEMP_COL2); -- null!!
END;

Answer 1

Don't open a cursor; just use the SELECT:
CREATE OR REPLACE PROCEDURE P_TEMP
(
pList0 OUT SYS_REFCURSOR
)
AS
TEMP_COL1 VARCHAR2(100);
TEMP_COL2 VARCHAR2(100);
BEGIN
WITH TEMP_TABLE(COLUMN_1, COLUMN_2 ,...., COLUMN_N) AS (
SELECT COL_1, COL_2, ... , COL_N
FROM your_table -- Need to select from a table.
)
SELECT COLUMN_1, COLUMN_2 -- Use the aliases you set in the sub-query factoring clause.
INTO TEMP_COL1, TEMP_COL2
FROM TEMP_TABLE
WHERE ROWNUM = 1 -- Only want a single row returned into the variables;
-- Or simpler
SELECT COL_1, COL_2
INTO TEMP_COL1, TEMP_COL2
FROM your_table
WHERE ROWNUM = 1 -- Only want a single row returned into the variables;
DBMS_OUTPUT.PUT_LINE(TEMP_COL1);
DBMS_OUTPUT.PUT_LINE(TEMP_COL2);
END;
/

Answer 2

You are missing the FETCH loop from the cursor. The easiest way to do this to use an implicit cursor:
CREATE OR REPLACE PROCEDURE P_TEMP AS
BEGIN
FOR rec IN
(
WITH temp_table(column_1, column_2 ,...., column_n) AS
(SELECT col_1, col_2, ... , col_n)
SELECT col_1, col_2
FROM temp_table
) LOOP
DBMS_OUTPUT.PUT_LINE(rec.col1);
DBMS_OUTPUT.PUT_LINE(rec.col2);
END LOOP;
END;
If, on the other hand, you only want to return the opened cursor, then you must not fetch from it yourself.
If you want to do both, i.e. fetch data yourself and return the cursor, then you must open the cursor twice for the same query. Once to process it yourself, once to give it to the caller to process it.
CREATE OR REPLACE PROCEDURE P_TEMP
(
out_cursor OUT SYS_REFCURSOR
)
AS
v_col1 VARCHAR2(100);
v_col2 VARCHAR2(100);
v_sql VARCHAR2(1000) := 'WITH temp_table ... SELECT col_1, col_2 FROM temp_table';
BEGIN
OPEN out_cursor FOR v_sql;
LOOP
FETCH out_cursor INTO v_col1, v_col2;
EXIT WHEN out_cursor%NOTFOUND;
DBMS_OUTPUT.PUT_LINE('col_1: ' || v_col1);
DBMS_OUTPUT.PUT_LINE('col_2: ' || v_col2);
END LOOP;
OPEN out_cursor FOR v_sql;
END;