A little bit about MySQL stored procedure exception handling

DROP PROCEDURE IF EXISTS ' Sp_model ';

DELIMITER;;
CREATE PROCEDURE ' Sp_model ' (in V_type INT)
BEGIN
/********** stored procedure template, combined • Return custom error message • Error exit • • Things Roll back • function ***********/
DECLARE v_test INT DEFAULT 0;

DECLARE v_err_no INT DEFAULT 0;
DECLARE v_err_msg VARCHAR (+) DEFAULT ' successful execution ';
DECLARE CONTINUE HANDLER for sqlexception,sqlwarning,not FOUND SET v_err_no=1;

--CREATE TABLE ' Test_error ' (
--' a ' int (one) not NULL,
--' B ' int (one) DEFAULT NULL,
--PRIMARY KEY (' a ')
--) Engine=innodb DEFAULT Charset=utf8;

--TRUNCATE TABLE test_error;
--Call Sp_model (1);
--SELECT * from Test_error;

START TRANSACTION;

IF V_type=1 Then
INSERT into Test_error (A, B) VALUES (+);
INSERT into Test_error (A, B) VALUES (+);

IF V_err_no=1 Then
SET v_err_msg= ' You have already inserted, do not repeat the insertion ~ ';
--LEAVE Label;
END IF;

SET v_test=1;

INSERT into Test_error (A, B) VALUES (3, ' a ');
IF V_err_no=1 Then
SET v_err_msg= ' size is not right, plug in ~ ';
LEAVE Label;
END IF;

INSERT into Test_error (A, B) VALUES (4,1);

SET v_test=2;

ELSE
SET v_err_msg= ' incoming parameter v_type incorrect ';
SET v_err_no=1; --Directly set the value of this variable to 1, and actively throw an exception
LEAVE Label;
END IF;

END Label;

IF V_err_no=1 Then
ROLLBACK;
ELSE
COMMIT;
END IF;

SELECT V_err_no as err_no,v_err_msg as Err_msg, v_test as TEST; --Return to execution results
END

;;

DELIMITER;

A little bit about MySQL stored procedure exception handling