获取插入行的字段值 [英] Get field value of inserted row

问题描述

我想编写一个函数，它为插入的行返回一列的值（本例中是一个自动递增的主键）。

基本上，我想插入一些新的数据，生成一个新的主键，然后获得该键。我可以简单地在表中查找最高主键，但也有可能其他人也可以运行该功能，并且我可以返回错误的键，对吗？

如何协商这个问题最简单的方法是什么？

正如评论所指出的，来自 MySQL文档：

  mysql> SELECT LAST_INSERT_ID（）; 
  - > 195 
  

这个 LAST_INSERT_ID（）函数不是受到像 SELECT MAX（id）这样的竞争条件的影响，因为它在MySQL中专用于您的连接。它返回为您的最后一次插入生成的ID，而不是任何人的最后一次插入。

I want to write a function that returns the value of a column (in this case, an auto-incrementing primary key) for a row that it inserts.

Essentially, I want to insert some new data, have a new primary key generated, then get that key. I could simply look for the highest primary key in the table, but it is possible that someone else could be running the function as well, and I could return the wrong key, right?

What's the simplest way to negotiate this problem?

解决方案

As pointed in the comments, from MySQL documentation:

mysql> SELECT LAST_INSERT_ID();
    -> 195

This LAST_INSERT_ID() function is not subject to a race condition like SELECT MAX(id) might be, because it's maintained within MySQL specific to your connection. It returns the ID generated for your last insert, not anybody's last insert.

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