MYSQL存储过程与函数_MySQL
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一、模式

二、存储过程与存储函数
语法如下:
CREATE PROCEDURE sp_name ([proc_parameter[,...]])
[characteristic ...] routine_body
CREATE FUNCTION sp_name ([func_parameter[,...]])
RETURNS type
[characteristic ...] routine_body
proc_parameter:
[ IN | OUT | INOUT ] param_name type
func_parameter:
param_name type
type:
Any valid MySQL data type
characteristic:
LANGUAGE SQL
| [NOT] DETERMINISTIC
| { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA }
| SQL SECURITY { DEFINER | INVOKER }
| COMMENT string
routine_body:
Valid SQL procedure statement or statements
例如:存储过程
mysql> use test;
mysql> delimiter // ###定义"//"为语句开始执行符号
mysql> create procedure simpleproc(out param1 int)
begin
select count(*) into param1 from t;
end
//
mysql>delimiter ; ####重新定义;为语句开始执行的符号
mysql> call simpleproc(@a);
mysql> select @a; ####a为一个变量
+------+
| @a |
+------+
| 1 |
+------+
区别:过程只处理一件事,并无返回值,但可以通过出口参数param1来返回处理后的值;而存储函数可以返回值
例如:存储函数
1.字符串拼接函数hello()
mysql> use test;
mysql> delimiter //
mysql> create function hello (t char(20)) returns char(50)
return concat(‘hello, ’ ,t, ‘!’);
//
mysql> delimiter ;
mysql> select hello(‘world’);
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