记一次SQLSever存储过程

编写存储过程：根据code，自动匹配对应数据，将对应字段减少num，然后返回计算后的结果num字段的值

USE dbo-- 对应的数据库
GO
 CREATE PROCEDURE z_sp_export @p_code CHAR ( 20 ), @p_num decimal(5,2),@r_num decimal(5,2)  OUTPUT AS 
UPDATE 
	 t_student
SET 
	student_no = student_no - @p_num 
WHERE
	 code  = @p_code;
SELECT
 	@r_num = student_no
FROM
	 t_student
WHERE
 	code = @p_code;
GO

调用存储过程并且返回值

DECLARE @return_value DECIMAL(5,2) EXEC z_sp_export '123',
'2',@return_value OUTPUT SELECT
@return_value AS '返回值'