#储存过程 中的变量定义

declare 变量名 类型 可选类型 -- 跟建表差不多

create procedure p()

  begin

    declare age int default(18);

    declare number int default 1;

    select age+number;

  end$

/*

mysql> create procedure p()

    ->   begin

    ->     declare age int default(18);

    ->     declare number int default 1;

    ->     select age+number;

    ->   end$

Query OK, 0 rows affected (0.00 sec)

mysql> call p$

+------------+

| age+number |

+------------+

|         19 |

+------------+

1 row in set (0.00 sec)

Query OK, 0 rows affected (0.01 sec)

*/

#储存过程 中， 变量可以运算

#运算结果赋修值给变量用: set age := 运算式

#set age := age + 2

#参数传递

mysql> create procedure p2(number int, age int)

    ->       begin

    ->         select age+number;

    ->       end$

Query OK, 0 rows affected (0.00 sec)

mysql> call p2(1,2)$

+------------+

| age+number |

+------------+

|          3 |

+------------+

1 row in set (0.00 sec)

Query OK, 0 rows affected (0.01 sec)

mysql>