问题描述
我必须在 MySQL 数据库中找到下一个可用的 id(如果数据库中有 5 个数据，我必须获取下一个可用的插入位置，即 6).我怎样才能做到这一点?我已经使用了 MAX(id)，但是当我从数据库中删除一些行时，它仍然保留它没有更新的旧最大值.
I have to find the next available id (if there are 5 data in database, I have to get the next available insert place which is 6) in a MySQL database. How can I do that?
I have used MAX(id), but when I delete some rows from the database, it still holds the old max value it didn't update.
推荐答案
我认为您永远无法确定 next id，因为有人可能会在您询问之后插入新行对于下一个 ID.你至少需要一个事务，如果我没记错的话，你只能在插入它之后获得实际使用的 id，至少这是处理它的常用方法——见 http://dev.mysql.com/doc/refman/5.0/en/getting-unique-id.html
I don't think you can ever be sure on the next id, because someone might insert a new row just after you asked for the next id. You would at least need a transaction, and if I'm not mistaken you can only get the actual id used after inserting it, at least that is the common way of handling it -- see http://dev.mysql.com/doc/refman/5.0/en/getting-unique-id.html
这篇关于在 MySQL 中查找下一个可用的 id的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！