MySQL函数和存储过程

Posted 2023-03-12 老李笔记

mysql函数和存储过程

1、函数

1. 创建随机字符串

DELIMITER $$
CREATE FUNCTION rand_string(n INT) RETURNS VARCHAR(255)
BEGIN
	DECLARE chars_str VARCHAR(100) DEFAULT 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
	DECLARE return_str VARCHAR(255) DEFAULT '';
	DECLARE i INT DEFAULT 0;
	WHILE i < n DO
		SET return_str =CONCAT(return_str,SUBSTRING(chars_str,FLOOR(1+RAND()*52),1));
		SET i = i +1;
	END WHILE;
	RETURN return_str;
END $$

2. 创建随机数

DELIMITER $$
CREATE FUNCTION rand_num() RETURNS INT(5)
BEGIN
	DECLARE i INT DEFAULT 0;
	SET i = FLOOR(100+RAND()*10);
RETURN i;
END $$

2、存储过程

1. 批量插入员工数据

DELIMITER $$
CREATE PROCEDURE insert_emp(IN START INT(10),IN max_num INT(10))
BEGIN
	DECLARE i INT DEFAULT 0;
	SET autocommit=0;
	REPEAT
	SET i = i+1;
	INSERT INTO emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) VALUES ((START+i),rand_string(6),'SALESMAN',0001,CURDATE(),2000,400,rand_num());
	UNTIL i = max_num
END REPEAT;
COMMIT;
END $$

2. 批量插入部门数据

DELIMITER $$
CREATE PROCEDURE insert_dept(IN START INT(10),IN max_num INT(10))
BEGIN
	DECLARE i INT DEFAULT 0;
	SET autocommit=0;
	REPEAT
	SET i = i+1;
	INSERT INTO dept (deptno,dname,loc) VALUES ((START+i),rand_string(10),rand_string(8));
	UNTIL i = max_num
END REPEAT;
COMMIT;
END $$

3、调用存储过程

DELIMITER;
CALL insert_dept(100,10);