mysql> create table student(id int not null auto_increment primary key,
-> name varchar(20),role varchar(20),sex varchar(4), age int );
Query OK, 0 rows affected (0.05 sec)mysql> insert into student values(1,'zhu','guest','boy',20),(2,'li','guest','boy
',23),(3,'zhao','admin','girl',24);
Query OK, 3 rows affected (0.02 sec)
Records: 3 Duplicates: 0 Warnings: 0mysql> select * from student;
+----+------+-------+------+------+
| id | name | role | sex | age |
+----+------+-------+------+------+
| 1 | zhu | guest | boy | 20 |
| 2 | li | guest | boy | 23 |
| 3 | zhao | admin | girl | 24 |
+----+------+-------+------+------+
3 rows in set (0.00 sec)mysql> delimiter //mysql> create procedure tt(in myrole varchar(10),out a int)
-> begin
-> select max(age) from student where role=myrole;
-> end
-> //
Query OK, 0 rows affected (0.00 sec)mysql> call tt('guest',@a)//
+----------+
| max(age) |
+----------+
| 23 |
+----------+
1 row in set (0.00 sec)Query OK, 0 rows affected (0.00 sec)
-> name varchar(20),role varchar(20),sex varchar(4), age int );
Query OK, 0 rows affected (0.05 sec)mysql> insert into student values(1,'zhu','guest','boy',20),(2,'li','guest','boy
',23),(3,'zhao','admin','girl',24);
Query OK, 3 rows affected (0.02 sec)
Records: 3 Duplicates: 0 Warnings: 0mysql> select * from student;
+----+------+-------+------+------+
| id | name | role | sex | age |
+----+------+-------+------+------+
| 1 | zhu | guest | boy | 20 |
| 2 | li | guest | boy | 23 |
| 3 | zhao | admin | girl | 24 |
+----+------+-------+------+------+
3 rows in set (0.00 sec)mysql> delimiter //mysql> create procedure tt(in myrole varchar(10),out a int)
-> begin
-> select max(age) from student where role=myrole;
-> end
-> //
Query OK, 0 rows affected (0.00 sec)mysql> call tt('guest',@a)//
+----------+
| max(age) |
+----------+
| 23 |
+----------+
1 row in set (0.00 sec)Query OK, 0 rows affected (0.00 sec)
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