1.語法
CREATE
[DEFINER = { user | CURRENT_USER }]
PROCEDURE sp_name ([proc_parameter[,...]])
[characteristic ...] routine_body
CREATE
[DEFINER = { user | CURRENT_USER }]
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:
COMMENT 'string'
| LANGUAGE SQL
| [NOT] DETERMINISTIC
| { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA }
| SQL SECURITY { DEFINER | INVOKER }
routine_body:
Valid SQL routine statement
參數詳解：
（1）DEFINER
表示創建存儲過程及函數的用戶，默認為當前用戶；
（2）func_parameter
表示存儲過程的參數。在Create Procedure 語句中，可以聲明一個或多個參數。當調用該存儲過程時，用戶必須給出所有的參數值，除非定義了參數的缺省值。若參數的形式以 @parameter=value 出現，則參數的次序可以不同，否則用戶給出的參數值必須與參數列表中參數的順序保持一致。若某一參數以@parameter=value 形式給出，那么其它參數也必須以該形式給出。一個存儲過程至多有1024 個參數。
（3）characteristic
- LANGUAGE SQL:表示此存儲過程和函數的創建語言；
- [NOT] DETERMINISTIC:表明輸入相同的參數會返回相同的結果，反之表示相同的參數不會是相同的結果，默認是not deterministic；
- -- CONTAINS SQL :子程序不包含讀或寫數據的語句；
- -- NO SQL : 子程序不包含SQL語句；
- -- READS SQL DATA :子程序包含讀數據的語句；
- -- MODIFIES SQL DATA : 子程序包含寫數據的語句；
- -- 如果這些特征沒有明確給定，默認的是CONTAINS SQL；
（4）SQL SECURITY { DEFINER | INVOKER }
子程序該用創建子程序者的許可來執行，還是使用調用者的許可來執行。默認值是DEFINER。
（5）COMMENT
是一個MySQL的擴展，它可以被用來描述存儲程序。這個信息被SHOW CREATE PROCEDURE和 SHOW CREATE FUNCTION語句來顯示。
2.存儲過程與函數特性
（1）存儲過程與函數的區別
- 函數調用有返回值
- 存儲過程調用用call語句，函數調用直接飲用函數名+參數
（2）Definer和sql security
- Definder是MySQL的特殊訪問控制手段，當數據庫當前沒有這個用戶權限時，執行存儲過程可能會報錯；
- sql security的值決定了調用存儲過程的方式，取值：definer（默認）或invoker；
- definer在執行時先驗證definer對應的用戶，如：cdq@127.0.0.1是否存在，以及是否具有執行存儲過程的權限，若沒有則報錯；
- invoker在執行存儲過程時判斷invoker，即調用該存儲過程的用戶是否有相應權限，若沒有則報錯
（3）IN，OUT，INOUT
只適用於存儲過程，對函數而言所有參數默認都是輸入參數
- IN用於把數值傳入到存儲過程中
- OUT用於輸出參數將數值傳遞給調用者
- INOUT輸入輸出參數把數據傳入到存儲過程，在存儲過程中修改后再傳遞給調用者
3.實例演示
（1）簡單存儲過程
mysql> delimiter //
mysql> create procedure simpleproc(in param1 int,out param2 int)
-> begin
-> select count(*) into param2 from students where sid > param1;
-> end//
Query OK, 0 rows affected (0.02 sec)
mysql> delimiter ;
mysql> call simpleproc(1,@a);
Query OK, 1 row affected (0.00 sec)
mysql> select @a;
+------+
| @a |
+------+
| 7 |
+------+
1 row in set (0.00 sec)
說明：
- delimiter命令是改變語句的結束符，MySQL默認結束符為；號，由於存儲過程和函數中的；號並不代表結束，所以要替換另外的結束符；
（2）簡單的函數
mysql> create function hello(s char(20))
-> returns char(50)
-> return concat('Hello',s,'!');
Query OK, 0 rows affected (0.00 sec)
mysql> select hello('world');
+----------------+
| hello('world') |
+----------------+
| Helloworld! |
+----------------+
1 row in set (0.00 sec)
（3）復雜的示例
mysql> delimiter //
mysql> create function simplefunc(param1 int)
-> returns int
-> begin
-> update students set gender=1 where sid=param1;
-> select count(*) into @a from students where sid > param1;
-> return @a;
-> end//
Query OK, 0 rows affected (0.00 sec)
mysql> delimiter ;
mysql> select * from students where sid=1;
+-----+--------+--------+---------+
| sid | sname | gender | dept_id |
+-----+--------+--------+---------+
| 1 | Andrew | 0 | 1 |
+-----+--------+--------+---------+
1 row in set (0.00 sec)
mysql> select simplefunc(1);
+---------------+
| simplefunc(1) |
+---------------+
| 7 |
+---------------+
1 row in set (0.03 sec)
mysql> select * from students where sid=1;
+-----+--------+--------+---------+
| sid | sname | gender | dept_id |
+-----+--------+--------+---------+
| 1 | Andrew | 1 | 1 |
+-----+--------+--------+---------+
1 row in set (0.01 sec)
說明：
- MySQL存儲過程和函數中也可以包含類似create和drop等DDL語句；
- rontine_body子句可以包含一個簡單的SQL語句，也可以包含多個SQL語句，通過begin...end將多個SQL語句包含在一起；
4.測試definer
[root@localhost ~]# mysql -uabc2 -p
Enter password:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| course |
+--------------------+
2 rows in set (0.01 sec)
mysql> use course;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> delimiter //
mysql> create procedure simpleproc2(IN param1 int,out param2 int)
-> begin
-> select count(*) into param2 from students where sid > param1;
-> end//
Query OK, 0 rows affected (0.00 sec)
[root@localhost ~]# mysql -p
Enter password:
mysql> use course;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> call simpleproc2(1,@a);
Query OK, 1 row affected (0.00 sec)
mysql> drop user 'abc2'@'localhost';
Query OK, 0 rows affected (0.00 sec)
mysql> call simpleproc2(1,@a);
ERROR 1449 (HY000): The user specified as a definer ('abc2'@'localhost') does not exist
查看存儲過程及函數的相關數據庫信息（在information_schema庫）
mysql> select ROUTINE_SCHEMA,ROUTINE_NAME,ROUTINE_TYPE,ROUTINE_BODY,ROUTINE_DEFINITION,DEFINER from ROUTINES where ROUTINE_SCHEMA = 'course';
+----------------+--------------+--------------+--------------+-------------------------------------------------------------------------------------------------------------------------------+----------------+
| ROUTINE_SCHEMA | ROUTINE_NAME | ROUTINE_TYPE | ROUTINE_BODY | ROUTINE_DEFINITION | DEFINER |
+----------------+--------------+--------------+--------------+-------------------------------------------------------------------------------------------------------------------------------+----------------+
| course | hello | FUNCTION | SQL | return concat('Hello',s,'!') | root@localhost |
| course | simplefunc | FUNCTION | SQL | begin
update students set gender=1 where sid=param1;
select count(*) into @a from students where sid > param1;
return @a;
end | root@localhost |
| course | simpleproc | PROCEDURE | SQL | begin
select count(*) into param2 from students where sid > param1;
end | root@localhost |
| course | simpleproc2 | PROCEDURE | SQL | begin
select count(*) into param2 from students where sid > param1;
end | abc2@localhost |
+----------------+--------------+--------------+--------------+-------------------------------------------------------------------------------------------------------------------------------+----------------+
mysql> alter procedure simpleproc2 sql security invoker;
Query OK, 0 rows affected (0.00 sec)
mysql> call simpleproc2(1,@a);
Query OK, 1 row affected (0.00 sec)
說明：
相關屬性短語只有咨詢含義，並不是強制性約束
- contains sql表明此存儲過程或函數不包含讀或者寫數據的語句，這是默認屬性；
- no sql表明此存儲過程或函數不包含SQL語句
- reads sql data表示此存儲過程包含諸如select的查詢數據的語句，但不包含插入或刪除數據的語句
- modifies sql data表示存儲過程包含插入或刪除數據的語句
5.刪除語句
DROP {procedure | function} {IF EXISTS} sp_name;
if exists用來避免在刪除一個本身不存在的存儲過程或函數時，MySQL返回錯誤；
mysql> drop procedure oldboy;
ERROR 1305 (42000): PROCEDURE course.oldboy does not exist
mysql> drop procedure if exists oldboy;
Query OK, 0 rows affected, 1 warning (0.00 sec)
6.查看存儲過程及函數
mysql> show create procedure simpleproc;
+------------+-------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
| Procedure | sql_mode | Create Procedure | character_set_client | collation_connection | Database Collation |
+------------+-------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
| simpleproc | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION | CREATE DEFINER=`root`@`localhost` PROCEDURE `simpleproc`(in param1 int,out param2 int)
begin
select count(*) into param2 from students where sid > param1;
end | utf8 | utf8_general_ci | latin1_swedish_ci |
+------------+-------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
mysql> show create function simplefunc;
+------------+-------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
| Function | sql_mode | Create Function | character_set_client | collation_connection | Database Collation |
+------------+-------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
| simplefunc | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION | CREATE DEFINER=`root`@`localhost` FUNCTION `simplefunc`(param1 int) RETURNS int(11)
begin
update students set gender=1 where sid=param1;
select count(*) into @a from students where sid > param1;
return @a;
end | utf8 | utf8_general_ci | latin1_swedish_ci |
+------------+-------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
1 row in set (0.01 sec)