Question

I am new to using procedures and cannot seem to get mine working. I am using MySQL v5.1.36 and inputing my code using MySQL Console on a WAMPP server. If I go to (re)create the procedure. I get error #1304 (42000).

mysql>  DELIMITER //
mysql>
mysql>  CREATE PROCEDURE modx.getCRID (IN x VARCHAR(255),OUT y INT)
    ->  BEGIN
    ->          DECLARE y INT;
    ->          SELECT id INTO y
    ->          FROM `modx`.coverage_region
    ->          WHERE `coverage_region`.name = x;
    ->  END//
ERROR 1304 (42000): PROCEDURE getCRID already exists
mysql>
mysql>  DELIMITER ;

However, if I try to use the procedure I get error #1305 (42000).

mysql> USE modx;
Database changed
mysql> SET @crID = modx.getCRID("South East");
ERROR 1305 (42000): FUNCTION modx.getCRID does not exist

If the procedure exists for one how can it not exist for the other? What am I doing wrong.

Answer 1

I believe the problems are

1. The first error occurs because you are attempting to re-create an existing procedure. If you were to drop the procedure first you would not get this error,
2. The second error is because PROCEDUREs are invoked with CALL statements, while FUNCTIONs are invoked as function references, as in your code. You must define a FUNCTION, not a PROCEDURE. The (MySQL documentation) says:

The CREATE FUNCTION statement is also
used in MySQL to support UDFs
(user-defined functions). See Section
21.2, “Adding New Functions to MySQL”. A UDF can be regarded as an external
stored function. Stored functions
share their namespace with UDFs. See
Section 8.2.3, “Function Name Parsing
and Resolution”, for the rules
describing how the server interprets
references to different kinds of
functions.

To invoke a stored procedure, use the
CALL statement (see Section 12.2.1,
“CALL Syntax”). To invoke a stored
function, refer to it in an
expression. The function returns a
value during expression evaluation.