stored procedure with parameters in MYSQL - mysql

Question

I have a question about the stored procedure:
Create a stored procedure named format_currency that accepts a character and a double number. It will return a VARCHAR(32) with the symbol in the front, followed by the number to 2 decimal places.
For example, format_currency('$', 123.4) should return $123.40
Here is my code:
CREATE OR REPLACE PROCEDURE format_currency(IN c VARCHAR2, IN n DOUBLE(9,2))
AS
BEGIN
SELECT CONCAT(c,',' n);
END;
It's not working, I have no idea how to write codes inside BEGIN and END.
Many Thanks for your help.
Henry

Answer 1

Instead of procedure I suggest to use function:
Code:
DELIMITER $$
DROP FUNCTION IF EXISTS test_f$$
CREATE FUNCTION test_f(a varchar(22),b double(9,2)) returns varchar(64)
BEGIN
SET #RET = (select concat(a,b));
return #RET;
END$$
DELIMITER ;
Test Run:
mysql> select test_f('$',123);
+-----------------+
| test_f('$',123) |
+-----------------+
| $123.00 |
+-----------------+
1 row in set (0.10 sec)
mysql>

Answer 2

DELIMITER\\
CREATE PROCEDURE format_currency (a CHAR, b DOUBLE(9,2))
BEGIN
declare ret VARCHAR(32);
set #ret = (SELECT CONCAT(a,b));
select #ret;
END
DELIMITER\\
call format_currency('$',123);

Answer 3

I had a similar question and nothing the other people answered worked for me in MySQL. Here is a working solution with 2 parameters as "SIGN" and "MONEY" and creating a variable called "NEWRESULT" that you delcare, set as 0, and then set as the concat of "SIGN" and "MONEY".
DELIMITER //
CREATE PROCEDURE format_currency`enter code here`
(IN SIGN char(1),IN MONEY double(9,2))
BEGIN
declare NEWRESULT char(8);
set NEWRESULT=0;
SET NEWRESULT=(SELECT CONCAT(SIGN,MONEY));
SELECT NEWRESULT;
END//
DELIMITER ;