Teradata Stored Procedure variables - sql

Question

I'm trying to create a stored procedure to create all possible combination of a table with itself. For now, I got this code, but it produces the following error:
Syntax error: expected something between the word 'A' and the integer '2'
Code:
CREATE MULTISET TABLE PRUEBA
(
CAMPO VARCHAR(10)
);
INSERT INTO PRUEBA VALUES('A');
INSERT INTO PRUEBA VALUES('B');
INSERT INTO PRUEBA VALUES('C');
REPLACE PROCEDURE TEST()
BEGIN
DECLARE a VARCHAR(255);
DECLARE b VARCHAR(225);
DECLARE qry VARCHAR(255);
DECLARE i INT;
DECLARE n INT;
SET a = 'SELECT * FROM PRUEBA A1 ';
SET b = ' WHERE ';
SET n = 3;
SET i = 1;
WHILE i < n DO
BEGIN
CASE i
WHEN 1 THEN
SET qry = a;
WHEN 2 THEN
SET a = a || 'CROSS JOIN PRUEBA A' || i ; -- Error in this part.
SET b = b || 'A' || (i-1) || '.CAMPO < A' || i || '.CAMPO';
SET qry = a || b;
ELSE
SET a = a || 'CROSS JOIN PRUEBA A' || i ;
SET b = b || 'AND A' || (i-1) || '.CAMPO < A' || i || '.CAMPO';
SET qry = a || b;
END CASE;
SET i = i + 1;
END;
END WHILE;
EXECUTE IMMEDIATE qry;
END;
CALL TEST();
I'd join the 'i' variable to create multiple alias for all cross tables.

Answer 1

Your i variable is an INTEGER. Try casting it as a VARCHAR() when you do your concatenations:
SET a = a || 'CROSS JOIN PRUEBA A' || CAST(i AS VARCHAR(2)) ; -- Error in this part.
SET b = b || 'A' || CAST((i-1) AS VARCHAR(2)) || '.CAMPO < A' ||
CAST(i AS VARCHAR(2)) || '.CAMPO';
You'll have to do this in the subsequent ELSE block as well.

Answer 2

Use explicit CAST or TRIM to avoid the leading blanks generated by implicit cast from INTEGER to VARCHAR. And you need to use a dynamic cursor to return the result of the SELECT to the caller.
REPLACE PROCEDURE TEST()
DYNAMIC RESULT SETS 1 --Allow returning data to caller
BEGIN
DECLARE a VARCHAR(255);
DECLARE b VARCHAR(225);
DECLARE qry VARCHAR(4096);
DECLARE i INT;
DECLARE n INT;
DECLARE csr1 CURSOR WITH RETURN FOR stmt1; --Declare a dynamic cursor
SET a = 'SELECT * FROM PRUEBA A1 ';
SET b = ' WHERE ';
SET n = 3;
SET i = 1;
WHILE i < n DO
BEGIN
CASE i
WHEN 1 THEN
SET qry = a;
WHEN 2 THEN
SET a = a || 'CROSS JOIN PRUEBA A' || TRIM(i) ;
SET b = b || 'A' || TRIM(i-1) || '.CAMPO < A' || TRIM(i) || '.CAMPO';
SET qry = a || b;
ELSE
SET a = a || 'CROSS JOIN PRUEBA A' || TRIM(i) ;
SET b = b || 'AND A' || TRIM(i-1) || '.CAMPO < A' || TRIM(i) || '.CAMPO';
SET qry = a || b;
END CASE;
SET i = i + 1;
END;
END WHILE;
PREPARE stmt1 FROM qry; --Prepare a dynamic SQL statement for the cursor
OPEN csr1; --Execute the SELECT statement
--Leave a WITH RETURN cursor open to return the result set
END;

Answer 3

if you're using bteq you might have to write the procedure into a file and load it with .compile directive.
once you are loggen in and supposing the file is /tmp/stored_procedure.sql
compile it like this:
.compile file='/tmp/stored_procedure.sql';