PLSQL DEFINE variable populate using cursor

Question

I need some help with dynamic SQL and cursor. I have stored procedure which has DEFINE variables. How I can populate DEFINE variable using cursor?

I want to use another table as source for cursor and insert these results to another table.

Here is simplified example about my problem:

CREATE OR REPLACE PROCEDURE usp_TEST
AS
BEGIN

DEFINE vTable = 'TABLE_NAME'; -- How I can create cursor loop, so I can loop and change this table name using another table as source?


INSERT INTO results
WITH CTE_main
AS
(
    SELECT 
        TABLE_NAME 
    FROM dest_TABLES
)
SELECT 
    'SELECT * FROM ' || '&vTable' || ' source INNER JOIN ' ||  cte.TABLE_NAME || ' dest ON source.ID = dest.ID;' AS query 
FROM CTE_main cte

END;

Source table contains only table names:

TABLE_ONE

TABLE_TWO

etc...

Result should be something like this:

SELECT * FROM TABLE_ONE source INNER JOIN DEST_ONE dest ON source.ID = dest.ID;
SELECT * FROM TABLE_ONE source INNER JOIN DEST_TWO dest ON source.ID = dest.ID;
SELECT * FROM TABLE_TWO source INNER JOIN DEST_ONE dest ON source.ID = dest.ID;
SELECT * FROM TABLE_TWO source INNER JOIN DEST_TWO dest ON source.ID = dest.ID;

Answer 1

Are you after something like:

WITH dest_tables AS (SELECT 'TABLE_ONE' table_name FROM dual UNION ALL
                     SELECT 'TABLE_TWO' table_name FROM dual),
        cte_main AS (SELECT 'DEST_ONE' table_name FROM dual UNION ALL
                     SELECT 'DEST_TWO' table_name FROM dual)
SELECT 'SELECT * FROM ' || dt.table_name || ' src INNER JOIN ' ||  cm.TABLE_NAME || ' dest ON src.ID = dest.ID;' AS query 
FROM   dest_tables dt
       CROSS JOIN cte_main cm
ORDER BY dt.table_name, cm.table_name;

QUERY
-------------------------------------------------------------------------
SELECT * FROM TABLE_ONE src INNER JOIN DEST_ONE dest ON src.ID = dest.ID;
SELECT * FROM TABLE_ONE src INNER JOIN DEST_TWO dest ON src.ID = dest.ID;
SELECT * FROM TABLE_TWO src INNER JOIN DEST_ONE dest ON src.ID = dest.ID;
SELECT * FROM TABLE_TWO src INNER JOIN DEST_TWO dest ON src.ID = dest.ID;

? (NB I used the two subqueries in the with-clause to mimic data in your tables; you wouldn't need those two subqueries, you'd just use your tables instead.)

No PL/SQL is required, just SQL. You could take the above statement and use it in an insert statement inside a PL/SQL program, though.