Mysql - How to quit/exit from stored procedure - mysql

Question

I have very simple question but i did't get any simple code to exit from SP using Mysql.
Can anyone share with me how to do that?
CREATE PROCEDURE SP_Reporting(IN tablename VARCHAR(20))
BEGIN
IF tablename IS NULL THEN
#Exit this stored procedure here
END IF;
#proceed the code
END;

Answer 1

CREATE PROCEDURE SP_Reporting(IN tablename VARCHAR(20))
proc_label:BEGIN
IF tablename IS NULL THEN
LEAVE proc_label;
END IF;
#proceed the code
END;

Answer 2

If you want an "early exit" for a situation in which there was no error, then use the accepted answer posted by #piotrm. Most typically, however, you will be bailing due to an error condition (especially in a SQL procedure).
As of MySQL v5.5 you can throw an exception. Negating exception handlers, etc. that will achieve the same result, but in a cleaner, more precise manner.
Here's how:
DECLARE CUSTOM_EXCEPTION CONDITION FOR SQLSTATE '45000';
IF <Some Error Condition> THEN
SIGNAL CUSTOM_EXCEPTION
SET MESSAGE_TEXT = 'Your Custom Error Message';
END IF;
Note SQLSTATE '45000' equates to "Unhandled user-defined exception condition". By default, this will produce an error code of 1644 (which has that same meaning). Note that you can throw other condition codes or error codes if you want (plus additional details for exception handling).
For more on this subject, check out:
https://dev.mysql.com/doc/refman/5.5/en/signal.html
How to raise an error within a MySQL function
http://www.databasejournal.com/features/mysql/mysql-error-handling-using-the-signal-and-resignal-statements.html
Addendum
As I'm re-reading this post of mine, I realized I had something additional to add. Prior to MySQL v5.5, there was a way to emulate throwing an exception. It's not the same thing exactly, but this was the analogue: Create an error via calling a procedure which does not exist. Call the procedure by a name which is meaningful in order to get a useful means by which to determine what the problem was. When the error occurs, you'll get to see the line of failure (depending on your execution context).
For example:
CALL AttemptedToInsertSomethingInvalid;
Note that when you create a procedure, there is no validation performed on such things. So while in something like a compiled language, you could never call a function that wasn't there, in a script like this it will simply fail at runtime, which is exactly what is desired in this case!

Answer 3

To handle this situation in a portable way (ie will work on all databases because it doesn’t use MySQL label Kung fu), break the procedure up into logic parts, like this:
CREATE PROCEDURE SP_Reporting(IN tablename VARCHAR(20))
BEGIN
IF tablename IS NOT NULL THEN
CALL SP_Reporting_2(tablename);
END IF;
END;
CREATE PROCEDURE SP_Reporting_2(IN tablename VARCHAR(20))
BEGIN
#proceed with code
END;

Answer 4

This works for me :
CREATE DEFINER=`root`#`%` PROCEDURE `save_package_as_template`( IN package_id int ,
IN bus_fun_temp_id int , OUT o_message VARCHAR (50) ,
OUT o_number INT )
BEGIN
DECLARE v_pkg_name varchar(50) ;
DECLARE v_pkg_temp_id int(10) ;
DECLARE v_workflow_count INT(10);
-- checking if workflow created for package
select count(*) INTO v_workflow_count from workflow w where w.package_id =
package_id ;
this_proc:BEGIN -- this_proc block start here
IF v_workflow_count = 0 THEN
select 'no work flow ' as 'workflow_status' ;
SET o_message ='Work flow is not created for this package.';
SET o_number = -2 ;
LEAVE this_proc;
END IF;
select 'work flow created ' as 'workflow_status' ;
-- To send some message
SET o_message ='SUCCESSFUL';
SET o_number = 1 ;
END ;-- this_proc block end here
END

Answer 5

Why not this:
CREATE PROCEDURE SP_Reporting(IN tablename VARCHAR(20))
BEGIN
IF tablename IS NOT NULL THEN
#proceed the code
END IF;
# Do nothing otherwise
END;

Answer 6

MainLabel:BEGIN
IF (<condition>) IS NOT NULL THEN
LEAVE MainLabel;
END IF;
....code
i.e.
IF (#skipMe) IS NOT NULL THEN /* #skipMe returns Null if never set or set to NULL */
LEAVE MainLabel;
END IF;

Answer 7

I think this solution is handy if you can test the value of the error field later. This is also applicable by creating a temporary table and returning a list of errors.
DROP PROCEDURE IF EXISTS $procName;
DELIMITER //
CREATE PROCEDURE $procName($params)
BEGIN
DECLARE error INT DEFAULT 0;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET error = 1;
SELECT
$fields
FROM $tables
WHERE $where
ORDER BY $sorting LIMIT 1
INTO $vars;
IF error = 0 THEN
SELECT $vars;
ELSE
SELECT 1 AS error;
SET #error = 0;
END IF;
END//
CALL $procName($effp);