在MySQL中创建带有IN和OUT参数的存储过程的方法

mysql> select * from employee;
+--------+----------+---------+--------+
| emp_id | emp_name | dept_id | salary |
+--------+----------+---------+--------+
|  103 | Jack   |    1 |  1400 |
|  104 | John   |    2 |  1450 |
|  108 | Alan   |    3 |  1150 |
|  107 | Ram   |  NULL |  600 |
+--------+----------+---------+--------+
4 rows in set (0.22 sec)

mysql> DELIMITER //
mysql> create procedure usp_totalEmployeeByDeparment(IN id INT)
  -> begin
  -> select count(*) as total from employee where dept_id = id;
  -> end//
Query OK, 0 rows affected (0.00 sec)

mysql> call usp_totalEmployeeByDeparment(2);
+-------+
| total |
+-------+
|   1 |
+-------+
1 row in set (0.06 sec)

mysql> DELIMITER //
mysql> create procedure usp_GetEmployeeName(IN id INT, OUT name VARCHAR(20))
  -> begin
  -> select emp_name into name from employee where emp_id = id;
  -> end//
Query OK, 0 rows affected (0.52 sec)
 
mysql> DELIMITER ;
 
mysql> call usp_GetEmployeeName(103, @name);
Query OK, 1 row affected (0.05 sec)
以MySQL命令行方式调用存过：
 
mysql> select @name;
+-------+
| @name |
+-------+
| Jack |
+-------+
1 row in set (0.00 sec)