MySql 存储过程实例(附完整注释)

    xiaoxiao2021-03-25  87

    MySql 存储过程实例(附完整注释)

    http://www.cnblogs.com/zhuawang/p/4185302.html

     MySql存储过程简单实例:                                                                                                        /********************* 创建表 *****************************/                                                     delimiter //                                                                                                          DROP TABLE if exists test //                                                                                                          CREATE TABLE test(                                                       id int(11) NULL                                                     ) //                                                                                                          /********************** 最简单的一个存储过程 **********************/                                                     drop procedure if exists sp//                                                      CREATE PROCEDURE sp() select 1 //                                                                                                            call sp()//                                                                                                           /********************* 带输入参数的存储过程  *******************/                                                                                                          drop procedure if exists sp1 //                                                                                                          create procedure sp1(in p int)                                                     comment 'insert into a int value'                                                     begin                                                       /* 定义一个整形变量 */                                                       declare v1 int;                                                                                                              /* 将输入参数的值赋给变量 */                                                       set v1 = p;                                                                                                              /* 执行插入操作 */                                                       insert into test(id) values(v1);                                                     end                                                     //                                                                                                          /* 调用这个存储过程  */                                                     call sp1(1)//                                                                                                          /* 去数据库查看调用之后的结果 */                                                     select * from test//                                                                                                           /****************** 带输出参数的存储过程 ************************/                                                                                                          drop procedure if exists sp2 //                                                     create procedure sp2(out p int)                                                     /*这里的DETERMINISTIC子句表示输入和输出的值都是确定的,不会再改变.我一同事说目前mysql并没有实现该功能,因此加不加都是NOT DETERMINISTIC的*/                                                     DETERMINISTIC                                                     begin                                                       select max(id) into p from test;                                                     end                                                     //                                                                                                          /* 调用该存储过程,注意:输出参数必须是一个带@符号的变量 */                                                     call sp2(@pv)//                                                                                                          /* 查询刚刚在存储过程中使用到的变量 */                                                     select @pv//                                                                                                                                                              /******************** 带输入和输出参数的存储过程 ***********************/                                                                                                          drop procedure if exists sp3 //                                                     create procedure sp3(in p1 int , out p2 int)                                                     begin                                                                                                            if p1 = 1 then                                                         /* 用@符号加变量名的方式定义一个变量,与declare类似 */                                                         set @v = 10;                                                       else                                                         set @v = 20;                                                       end if;                                                                                                              /* 语句体内可以执行多条sql,但必须以分号分隔 */                                                       insert into test(id) values(@v);                                                       select max(id) into p2 from test;                                                                                                            end                                                     //                                                                                                          /* 调用该存储过程,注意:输入参数是一个值,而输出参数则必须是一个带@符号的变量 */                                                     call sp3(1,@ret)//                                                                                                          select @ret//                                                                                                          /***************** 既做输入又做输出参数的存储过程 ***************************************/                                                                                                          drop procedure if exists sp4 //                                                     create procedure sp4(inout p4 int)                                                     begin                                                        if p4 = 4 then                                                           set @pg = 400;                                                        else                                                           set @pg = 500;                                                        end if;                                                                                                                 select @pg;                                                                                                             end//                                                                                                          call sp4(@pp)//                                                                                                          /* 这里需要先设置一个已赋值的变量,然后再作为参数传入 */                                                     set @pp = 4//                                                     call sp4(@pp)//                                                                                                                                                               /********************************************************/

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