mysql存储过程原理与使用方法详解

delimiter //
create procedure p1()
BEGIN
  select * from blog;
  INSERT into blog(name,sub_time) values("xxx",now());
END //
delimiter ;

#在mysql中调用
call p1()

#在python中基于pymysql调用
cursor.callproc('p1')
print(cursor.fetchall())

mysql> select * from emp;
+----+----------+-----+--------+
| id | name   | age | dep_id |
+----+----------+-----+--------+
| 1 | zhangsan | 18 |   1 |
| 2 | lisi   | 19 |   1 |
| 3 | egon   | 20 |   2 |
| 5 | alex   | 18 |   2 |
+----+----------+-----+--------+
4 rows in set (0.30 sec)
mysql> delimiter //
mysql> create procedure p2(in n1 int, in n2 int)
  -> begin
  ->  select * from emp where id >n1 and id <n2;
  -> end //
Query OK, 0 rows affected (0.28 sec)
mysql> delimiter ;
mysql> call p2(1,3)
  -> ;
+----+------+-----+--------+
| id | name | age | dep_id |
+----+------+-----+--------+
| 2 | lisi | 19 |   1 |
+----+------+-----+--------+
1 row in set (0.07 sec)
Query OK, 0 rows affected (0.07 sec)

#在python中基于pymysql调用
cursor.callproc('p2',(1,3))
print(cursor.fetchall())

mysql> delimiter //
mysql> create procedure p3( in n1 int, out res int)
  -> begin
  ->  select * from emp where id >n1;
  ->  set res=1;
  -> end //
Query OK, 0 rows affected (0.28 sec)
mysql> delimiter ;
mysql> set @res=0;
Query OK, 0 rows affected (0.00 sec)
mysql> call p3(3,@res);
+----+------+-----+--------+
| id | name | age | dep_id |
+----+------+-----+--------+
| 5 | alex | 18 |   2 |
+----+------+-----+--------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
mysql> select @res;
+------+
| @res |
+------+
|  1 |
+------+
1 row in set (0.00 sec)

#在python中基于pymysql调用
cursor.callproc('p3',(3,0)) #0相当于set @res=0
print(cursor.fetchall()) #查询select的查询结果
cursor.execute('select @_p3_0,@_p3_1;') #@p3_0代表第一个参数，@p3_1代表第二个参数，即返回值
print(cursor.fetchall())

delimiter //
create procedure p4(
  inout n1 int
)
BEGIN
  select * from blog where id > n1;
  set n1 = 1;
END //
delimiter ;

#在mysql中调用
set @x=3;
call p4(@x);
select @x;

#在python中基于pymysql调用
cursor.callproc('p4',(3,))
print(cursor.fetchall()) #查询select的查询结果
cursor.execute('select @_p4_0;')
print(cursor.fetchall())

#介绍
delimiter //
      create procedure p4(
        out status int
      )
      BEGIN
        1. 声明如果出现异常则执行{
          set status = 1;
          rollback;
        }
        开始事务
          -- 由秦兵账户减去100
          -- 方少伟账户加90
          -- 张根账户加10
          commit;
        结束
        set status = 2;
      END //
      delimiter ;
#实现
delimiter //
create PROCEDURE p5(
  OUT p_return_code tinyint
)
BEGIN 
  DECLARE exit handler for sqlexception 
  BEGIN 
    -- ERROR 
    set p_return_code = 1; 
    rollback; 
  END; 
  DECLARE exit handler for sqlwarning 
  BEGIN 
    -- WARNING 
    set p_return_code = 2; 
    rollback; 
  END; 
  START TRANSACTION; 
    DELETE from tb1; #执行失败
    insert into blog(name,sub_time) values('yyy',now());
  COMMIT; 
  -- SUCCESS 
  set p_return_code = 0; #0代表执行成功
END //
delimiter ;

#在mysql中调用存储过程
set @res=123;
call p5(@res);
select @res;

#在python中基于pymysql调用存储过程
cursor.callproc('p5',(123,))
print(cursor.fetchall()) #查询select的查询结果
cursor.execute('select @_p5_0;')
print(cursor.fetchall())

-- 无参数
call proc_name()
-- 有参数，全in
call proc_name(1,2)
-- 有参数，有in，out，inout
set @t1=0;
set @t2=3;
call proc_name(1,2,@t1,@t2)

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import pymysql
conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='123', db='t1')
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
# 执行存储过程
cursor.callproc('p1', args=(1, 22, 3, 4))
# 获取执行完存储的参数
cursor.execute("select @_p1_0,@_p1_1,@_p1_2,@_p1_3")
result = cursor.fetchall()
conn.commit()
cursor.close()
conn.close()
print(result)

drop procedure proc_name;