So schreiben Sie eine gespeicherte MySQL-Prozedur

CREATE PROCEDURE  过程名([[IN|OUT|INOUT] 参数名 数据类型[,[IN|OUT|INOUT] 参数名 数据类型…]]) [特性 ...] 过程体
DELIMITER //  
CREATE PROCEDURE myproc(OUT s int)    
BEGIN      
SELECT COUNT(*) INTO s FROM students;    
END    
//
DELIMITER ;

-- ----------------------------
-- Procedure structure for `proc_adder`
-- ----------------------------DROP PROCEDURE IF EXISTS `proc_adder`;
DELIMITER ;;CREATE DEFINER=`root`@`localhost` PROCEDURE `proc_adder`(IN a int, IN b int, OUT sum int)BEGIN
    #Routine body goes here...
 
    DECLARE c int;
    if a is null then set a = 0;
    end if;
  
    if b is null then set b = 0;
    end if;set sum  = a + b;END
;;
DELIMITER ;

set @b=5;
call proc_adder(2,@b,@s);
select @s as sum;