MySQL5.5创建存储过程和函数

执行CREATE PROCEDURE和CREATE FUNCTION语句需要CREATE ROUTINE权限。

查看neo用户现有权限


授权
MySQL> grant create routine on fire.* to neo;
Query OK, 0 rows affected (0.12 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.02 sec)

创建存储过程



注意：在命令行缩进时，不要用tab，要使用空格，否则会报下面的错

执行存储过程


授权
mysql> grant execute on fire.* to neo;
Query OK, 0 rows affected (0.04 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)





也可以直接在Navicat里面执行


编辑存储过程


调用存储过程




创建不含参数的存储过程，和Oracle不同的是，存储过程名字后面必须要有()
mysql> delimiter $$
mysql> create procedure proc_Subscribers_update()
    -> begin
    -> DECLARE v_count INT;
    -> select ifnull(max(a),0) into v_count from t2;
    -> while v_count < 2 do
    -> select concat('the maximum value is ',v_count);
    -> set v_count = v_count+1;
    -> end while;
    -> end$$
Query OK, 0 rows affected (0.06 sec)
delimiter $$
删除存储过程


需要授予alter routine权限

mysql> grant alter routine on fire.* to neo;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)



在mysql客户端中创建调用存储过程

MariaDB [test]> delimiter //
MariaDB [test]> create procedure simpleproc(out param1 int)
    -> begin
    -> select count(*) into param1 from t;
    -> end//
Query OK, 0 rows affected (0.12 sec)
MariaDB [test]> delimiter ;
MariaDB [test]> CALL simpleproc(@a);
Query OK, 1 row affected (0.08 sec)
MariaDB [test]> select @a;
+------+
| @a   |
+------+
|    1 |
+------+
1 row in set (0.00 sec)

在调用的时候，如果参数不带@，会报下面的错
mysql> call proc_test(a,b);

查看存储过程的状态

MariaDB [test]> show procedure status like 'simpleproc'\G
*************************** 1. row ***************************
                  Db: test
                Name: simpleproc
                Type: PROCEDURE
             Definer: root@localhost
            Modified: 2016-07-01 08:16:20
             Created: 2016-07-01 08:16:20
       Security_type: DEFINER
             Comment: 
character_set_client: utf8
collation_connection: utf8_general_ci
  Database Collation: utf8_general_ci
1 row in set (0.00 sec)
查看存储过程的定义

MariaDB [test]> show create procedure simpleproc\G
*************************** 1. row ***************************
           Procedure: simpleproc
            sql_mode: NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
    Create Procedure: CREATE DEFINER=`root`@`localhost` PROCEDURE `simpleproc`(out param1 int)
begin
select count(*) into param1 from t;
end
character_set_client: utf8
collation_connection: utf8_general_ci
  Database Collation: utf8_general_ci
1 row in set (0.00 sec)
创建函数

MySQL的传入参数不能设置默认值，否则会报错
mysql> delimiter $$
mysql> CREATE FUNCTION format_selectQuery (THE_TABLE_NAME VARCHAR(75), THE_COLUMNS_NAME VARCHAR(75), THE_CONDITION VARCHAR(75) DEFAULT NULL) RETURNS VARCHAR(200) DETERMINISTIC
    -> BEGIN
    ->     /*SELECT concat(' WHERE ', THE_CONDITION) INTO @WHERE_CLAUSE;
   /*>     IF THE_CONDITION IS NULL THEN
   /*> SET @WHERE_CLAUSE = NULL;
   /*> END IF;
   /*>     RETURN concat('SELECT ', THE_COLUMNS_NAME, ' FROM ', THE_TABLE_NAME, @WHERE_CLAUSE);*/
    ->     RETURN 1;
    -> END $$
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DEFAULT '') RETURNS VARCHAR(200) DETERMINISTIC
BEGIN
    
    RETURN 1;
END' at line 1
mysql> delimiter ;

需要注意的是，在MySQL里，创建函数中在函数声明后面的返回关键字是RETURNS


执行函数





需要注意的是，函数或存储过程里面的参数声明顺序，顺序有误，容易引起语法报错
delimiter $$
CREATE FUNCTION is_ChangeDescColumnExist (THE_VERSION_LEVEL_TABLE_NAME VARCHAR(35)) RETURNS INT DETERMINISTIC
    BEGIN
/* 声明变量*/
    DECLARE nbr INT;
/* 声明异常*/
    DECLARE CONTINUE HANDLER FOR NOT FOUND set nbr = 1;
/* 给变量赋值 */
    SET nbr =0;       
        select count(*) into nbr from information_schema.columns where table_name = THE_VERSION_LEVEL_TABLE_NAME and
        (column_name ='C_CHANGE_DESCRIPTION');
        IF nbr = 1 THEN
            RETURN 1;
        ELSE        
            RETURN 0;
        END IF;
    END$$
delimiter ;

将上面的顺序放置错误，则会引起报错
mysql> CREATE FUNCTION is_ChangeDescColumnExist (THE_VERSION_LEVEL_TABLE_NAME VARCHAR(35)) RETURNS INT DETERMINISTIC
    ->     BEGIN
    ->     DECLARE nbr INT;
    ->     SET nbr =0;
    ->     DECLARE CONTINUE HANDLER FOR NOT FOUND set nbr = 10;
    ->           
    ->         select count(*) into nbr from information_schema.columns where table_name = THE_VERSION_LEVEL_TABLE_NAME and
    ->         (column_name ='C_CHANGE_DESCRIPTION');
    ->         IF nbr = 1 THEN
    ->             RETURN 1;
    ->         ELSE
ELSE    ELSEIF  
    ->         ELSE
    ->             RETURN 0;
    ->         END IF;
    ->     END$$
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DECLARE CONTINUE HANDLER FOR NOT FOUND set nbr = 10;
          
        select c' at line 5

创建两个函数，返回两种变量，一种是DECLARE变量，一种是@变量
delimiter $$
    CREATE FUNCTION is_TableMigrated (THE_VERSION_LEVEL_TABLE_NAME VARCHAR(20)) RETURNS INTEGER DETERMINISTIC
    BEGIN
    DECLARE nbr integer;
    SET nbr =222;
RETURN nbr;
END$$
delimiter ;

delimiter $$
    CREATE FUNCTION is_TableMigrated (THE_VERSION_LEVEL_TABLE_NAME VARCHAR(20)) RETURNS INTEGER DETERMINISTIC
    BEGIN
    DECLARE nbr integer;
    SET @nbr2 =22222;
RETURN @nbr2;
END$$
delimiter ;

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