存储过程与普通查询的行为不同

Question

我遇到了一个问题，那就是我执行了一个存储过程，它在数据库中的几个表上执行更新。错误是这样完成的，每次只有一个字段（代表相同的记录ID）更新为新的ID。这是spoc：

DROP PROCEDURE IF EXISTS feeds_transfer; 
DELIMITER $$ 
CREATE PROCEDURE feeds_transfer(IN original_owner INT, IN new_owner INT, IN feed_id INT) 
    BEGIN 
     UPDATE `events` SET `user_id` = new_owner WHERE `user_id` = original_owner AND `feed_id` = feed_id; 
     UPDATE `feeds` SET `partner_id` = new_owner WHERE `partner_id` = original_owner AND `id` = feed_id; 
    UPDATE `ics_uploads` SET `user_id` = new_owner WHERE `user_id` = original_owner AND `context_type` = 'feed' AND `context_id` = feed_id; 
    UPDATE `images` SET `user_id` = new_owner WHERE `user_id` = original_owner AND `context` = 'feed' AND `context_id` = feed_id; 
    UPDATE `private_feed_invitees` SET `user_id` = new_owner WHERE `user_id` = original_owner AND `feed_id` = feed_id; 
     UPDATE `subscribed_feeds` SET `user_id` = new_owner WHERE `user_id` = original_owner AND `feed_id` = feed_id; 
    END $$ 
DELIMITER ; 

会发生什么是subscribed_feeds表将更新其中user_id = original_owner的每个记录。它就像忽略了feed_id = feed_id

Answer 1

好的，这里发生的并不是feed_id = feed_id子句被忽略，它始终是真实的，所以它总是触发更多的更新，而不是希望的更新。这个故事的寓意是，你永远不应该把你的存储过程的输入变量命名为与你打算进行逻辑检查的任何字段相同的东西。