Mysql存储过程之简单使用

基础查询
首先创建一张students学生表，增加字段与插入数据如下



创建不带参数的存储过程查看学生个数

DROP PROCEDURE IF EXISTS select_students_count;  -- 没有括号()

DELIMITER ;;
CREATE PROCEDURE `select_students_count`()
BEGIN
SELECT count(id) from students;
END;;
DELIMITER ;

执行存储过程

call select_students_count();

带参数的存储过程根据城市查询总数

DROP PROCEDURE IF EXISTS select_students_by_city_count;

DELIMITER ;;
CREATE PROCEDURE `select_students_by_city_count`(
in _city varchar(225)
)
BEGIN
SELECT count(id) from students where city = _city;
END;;
DELIMITER ;

执行存储过程

call select_students_by_city_count('杭州');

带有输出参数的存储过程
根据姓名查询的学生信息，返回学生的城市

DROP PROCEDURE IF EXISTS select_students_by_name;

DELIMITER ;;
CREATE PROCEDURE `select_students_by_name`(
in _name varchar(225),   -- 输入参数
out _city varchar(225),  -- 输出参数
inout _age int(11)       -- 输入输出参数
)
BEGIN
SELECT city  from students where name = _name and age = _age into _city;
END;;
DELIMITER ;

执行存储过程

set @_age = 20;
set @_name = 'jack';
call select_students_by_name(@_name, @_city, @_age);
select @_city as city, @_age as age;

MySQL支持IN(传递给存储过程)，OUT(从存储过程传出)和INOUT(对存储过程传入和传出)类型的参数。存储过程的代码位于BEGIN和END语句内，如前所见，它们是一系列SELECT语句，用来检索值，然后保存到相应的变量(通过指定INTO关键字)带有通配符的存储过程通配符，在参数值赋值时，加上相应的通配符

DROP PROCEDURE IF EXISTS select_students_by_likename;

DELIMITER ;;
CREATE PROCEDURE `select_students_by_likename`(
in _likename varchar(225)
)
BEGIN
set _likename = '%s%';  -- 默认值
SELECT *  from students where name like _likename;
END;;
DELIMITER ;

执行存储过程

call select_students_by_likename('%s%');

使用存储过程进行增删改新增 新增学生信息

DROP PROCEDURE IF EXISTS insert_student;

DELIMITER ;;
CREATE PROCEDURE `insert_student`(
_id int,
_name varchar(225),
_age int,
_city varchar(225)
)
BEGIN
INSERT INTO students(ID,name,age,city) VALUES(_id,_name,_age,_city);
END;;
DELIMITER ;

执行存储过程

call insert_student(5,'张三',19,'上海');

执行完后表中就多了一条数据


修改根据学生ID，更新学生信息

DROP PROCEDURE IF EXISTS update_student;

DELIMITER ;;
CREATE PROCEDURE `update_student`(
_id int,
_name varchar(225),
_age int,
_city varchar(225)
)
BEGIN
UPDATE  students SET name=_name, age=_age, city=_city where ID = _id;
END;;
DELIMITER ;

执行存储过程

call update_student(5,'amy',22,'杭州');

删除根据ID，删除某学生记录

DROP PROCEDURE IF EXISTS delete_student_by_id;

DELIMITER ;;
CREATE PROCEDURE `delete_student_by_id`(
_id int
)
BEGIN
DELETE FROM students where ID = _id;
END;;
DELIMITER ;

执行存储过程

call delete_student_by_id(5);

students表中id为5的那条记录就删除啦！