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

CREATE PROCEDURE myproc(OUT s int)
    BEGIN
      SELECT COUNT(*) INTO s FROM students;
    END

DROP PROCEDURE IF EXISTS in_param;
DELIMITER //
CREATE PROCEDURE in_param (IN para_in INT)

BEGIN
SELECT * from table1 WHERE age = para_in;
END ;
//DELIMITER

#调用
SET @para_in = 25;

CALL in_param (@para_in);