【MYSQL】AUTO_INCREMENT超过表中该字段的最大值

本文针对AUTO_INCREMENT超过表中该字段的最大值时产生的问题及应对方案进行了说明。

表的自动新增AUTOINCREMENT超过数据中该字段的最大值

在数据表中会发现AUTO_INCREMENT的值不等于表中字段最大值+1,可能原因有以下几种:

1.步长不为1,则AUTO_INCREMENT=最大值+步长。

复制代码
mysql> show variables like 'auto_inc%';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| auto_increment_increment | 10    |
| auto_increment_offset    | 5     |
+--------------------------+-------+
2 rows in set (0.00 sec)
mysql> select * from tianyiy;
+-----+
| uid |
+-----+
|   5 |
|  15 |
|  25 |
+-----+
3 rows in set (0.00 sec)
mysql> show create table tianyiy;
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                          |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tianyiy | CREATE TABLE `tianyiy` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=35 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

2.直接修改表的AUTO_INCREMENT,会导致AUTO_INCREMENT变化。

复制代码
mysql> select * from tianyiyun;
+-----+------+
| uid | user |
+-----+------+
| -30 | k    |
|   1 | a    |
|   2 | b    |
|   3 | c    |
|   4 | d    |
|   5 | e    |
|   6 | f    |
|   7 | g    |
|   8 | h    |
|  30 | j    |
|  99 | i    |
+-----+------+
11 rows in set (0.00 sec)
mysql> show create table tianyiyun;
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table     | Create Table                                                                                                                                                                                                                  |
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tianyiyun | CREATE TABLE `tianyiyun` (
  `uid` mediumint(9) NOT NULL AUTO_INCREMENT,
  `user` char(10) COLLATE utf8mb4_bin NOT NULL,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=100 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> alter table tianyiyun AUTO_INCREMENT=99;
Query OK, 0 rows affected (0.00 sec)
Records: 0  Duplicates: 0  Warnings: 0
mysql> show create table tianyiyun;
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table     | Create Table                                                                                                                                                                                                                  |
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tianyiyun | CREATE TABLE `tianyiyun` (
  `uid` mediumint(9) NOT NULL AUTO_INCREMENT,
  `user` char(10) COLLATE utf8mb4_bin NOT NULL,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=100 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

3.未提交的事务或回滚的事务,会导致AUTO_INCREMENT增长,但回滚后不会下降。

复制代码
mysql> show create table tiayiyun_test;
+---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table         | Create Table                                                                                                                                                               |
+---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tiayiyun_test | CREATE TABLE `tiayiyun_test` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+---------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> select * from tiayiyun_test;
+-----+
| uid |
+-----+
|   1 |
|   2 |
|   3 |
|   4 |
|   5 |
|   6 |
+-----+
6 rows in set (0.00 sec)
mysql> begin;
Query OK, 0 rows affected (0.00 sec)
mysql> insert into tiayiyun_test values (0),(0),(0);
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0
mysql> select * from tiayiyun_test;
+-----+
| uid |
+-----+
|   1 |
|   2 |
|   3 |
|   4 |
|   5 |
|   6 |
|  15 |
|  25 |
|  35 |
+-----+
9 rows in set (0.00 sec)
mysql> show create table tiayiyun_test;
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table         | Create Table                                                                                                                                                                |
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tiayiyun_test | CREATE TABLE `tiayiyun_test` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=45 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> rollback;
Query OK, 0 rows affected (0.01 sec)
mysql> select * from tiayiyun_test;
+-----+
| uid |
+-----+
|   1 |
|   2 |
|   3 |
|   4 |
|   5 |
|   6 |
+-----+
6 rows in set (0.00 sec)
mysql> show create table tiayiyun_test;
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table         | Create Table                                                                                                                                                                |
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tiayiyun_test | CREATE TABLE `tiayiyun_test` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=45 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

4.数据插入后,AUTO_INCREMENT变化,然后删除对应的数据行,AUTO_INCREMENT不会下降。

复制代码
mysql> show create table tiayiyun_test;
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table         | Create Table                                                                                                                                                                |
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tiayiyun_test | CREATE TABLE `tiayiyun_test` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=45 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> select * from tiayiyun_test;
+-----+
| uid |
+-----+
|   1 |
|   2 |
|   3 |
|   4 |
|   5 |
|   6 |
+-----+
6 rows in set (0.00 sec)
mysql> insert into tiayiyun_test values (0),(0),(0);
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0
mysql> select * from tiayiyun_test;
+-----+
| uid |
+-----+
|   1 |
|   2 |
|   3 |
|   4 |
|   5 |
|   6 |
|  45 |
|  55 |
|  65 |
+-----+
9 rows in set (0.00 sec)
mysql> show create table tiayiyun_test;
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table         | Create Table                                                                                                                                                                |
+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tiayiyun_test | CREATE TABLE `tiayiyun_test` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=75 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+---------------
相关推荐
AAA修煤气灶刘哥10 小时前
后端人速藏!数据库PD建模避坑指南
数据库·后端·mysql
程序新视界11 小时前
学习MySQL绕不开的两个基础概念:聚集索引与非聚集索引
mysql
RestCloud14 小时前
跨境数据传输:ETL如何处理时区与日期格式差异
mysql·api
RestCloud14 小时前
揭秘 CDC 技术:让数据库同步快人一步
数据库·api
得物技术17 小时前
MySQL单表为何别超2000万行?揭秘B+树与16KB页的生死博弈|得物技术
数据库·后端·mysql
xiaok18 小时前
mysql中怎么创建一个可控权限数据库账号密码给到开发者
mysql
可涵不会debug21 小时前
【IoTDB】时序数据库选型指南:工业大数据场景下的技术突围
数据库·时序数据库
ByteBlossom21 小时前
MySQL 面试场景题之如何处理 BLOB 和CLOB 数据类型?
数据库·mysql·面试
玉衡子21 小时前
九、MySQL配置参数优化总结
java·mysql
麦兜*21 小时前
MongoDB Atlas 云数据库实战:从零搭建全球多节点集群
java·数据库·spring boot·mongodb·spring·spring cloud