mysql - MySQL 存储过程的 INOUT 示例

Question

能否给我一个MySQL存储过程中INOUT的简单例子？

Answer 1

我认为搜索 Google 会为您提供大量示例!!
一个(取自here)

DELIMITER $$
DROP PROCEDURE IF EXISTS `test`.`get_users` $$
CREATE PROCEDURE `get_users`(
    IN firstName VARCHAR(100),
    OUT totalUsers INT
)
BEGIN
    SELECT COUNT(*) INTO totalUsers
    FROM users
    WHERE first_name = firstName;
    SELECT * FROM users
    WHERE first_name = firstName;
END $$
DELIMITER ;

帖子说:

Notice there are two statements in the body of this stored procedure. The first select count(*) statement counts the total number of people who’s first name is equal to the in variable firstName. Once it’s gets the count, it sets the out variable totalUsers to that value.

The next statement is a simple select. This will select all fields for users who’s first name is equal to the in variable firstName and return the recordset. So by calling this stored procedure and passing in two parameters (first name, total), a recordset will be returned and an out variable will be set – that can then be queried.

已编辑:
如 MySQL website :

CREATE PROCEDURE p (OUT ver_param VARCHAR(25), INOUT incr_param INT)
BEGIN
  # Set value of OUT parameter
  SELECT VERSION() INTO ver_param;
  # Increment value of INOUT parameter
  SET incr_param = incr_param + 1;
END;