setting variable in case of exception - mysql

Question

I have a stored procedure which will set my customized error as well as set an out variable to some value . I tried the following procedure .
***delimiter //
drop procedure if exists test_dalpu //
create procedure test_dalpu(out out_value int)
begin
DECLARE EXIT HANDLER FOR SQLSTATE '22001'
BEGIN
set out_value = 1;
SIGNAL SQLSTATE '22001' SET
MYSQL_ERRNO = 2,
MESSAGE_TEXT = 'Too long ';
END;
insert into abc_test values ( 5,"eerrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr");***
end//
delimiter ;
Then after executing
**call test_dalpu(#out_value);**
I got the correct output as Error code 2 Too long as expected, But after that If I do
select #out_value;
Am getting the value as null instead of 1 .
Is it the correct way?

Answer 1

Try:
mysql> DROP PROCEDURE IF EXISTS `test_dalpu`;
Query OK, 0 rows affected (0.00 sec)
mysql> DROP TABLE IF EXISTS `abc_test`;
Query OK, 0 rows affected (0.00 sec)
mysql> CREATE TABLE IF NOT EXISTS `abc_test` (
-> `id` INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-> `description` CHAR(10)
-> );
Query OK, 0 rows affected (0.00 sec)
mysql> DELIMITER //
mysql> CREATE PROCEDURE `test_dalpu`(`out_value` VARCHAR(64))
-> BEGIN
-> DECLARE EXIT HANDLER FOR SQLSTATE '22001'
-> BEGIN
-> ROLLBACK;
-> SET #`set_variable` := CONCAT('SET #`', `out_value`, '` := 1');
-> PREPARE `stmt` FROM #`set_variable`;
-> EXECUTE `stmt`;
-> DEALLOCATE PREPARE `stmt`;
-> SIGNAL SQLSTATE '22001' SET
-> MYSQL_ERRNO = 2,
-> MESSAGE_TEXT = 'Too long';
-> END;
-> START TRANSACTION;
-> INSERT INTO `abc_test`
-> (`description`)
-> VALUES
-> ('ABCDEFGHIJK');
-> COMMIT;
-> END//
Query OK, 0 rows affected (0.00 sec)
mysql> DELIMITER ;
mysql> SET #`out_value` := NULL;
Query OK, 0 rows affected (0.00 sec)
mysql> CALL `test_dalpu`('out_value');
ERROR 2 (22001): Too long
mysql> SHOW WARNINGS;
+-------+------+----------+
| Level | Code | Message |
+-------+------+----------+
| Error | 2 | Too long |
+-------+------+----------+
1 row in set (0.00 sec)
mysql> SELECT #`out_value`;
+--------------+
| #`out_value` |
+--------------+
| 1 |
+--------------+
1 row in set (0.00 sec)