今天建了一张表，设置其"id"属性为自动增加类型，但是在查看所有数据的时候，却发现"id"的值不是连续增加的。建表的语法如下：
mysql> create table person_list -> ( -> id int auto_increment unique, -> name varchar(15) not null, -> sex varchar(15) default "中", -> ID_C varchar(20) not null unique, -> vocation varchar(8), -> salary float default 0.0 -> )charset=utf8;Query OK, 0 rows affected (0.09 sec)mysql> desc person_list;+----------+-------------+------+-----+---------+----------------+| Field | Type | Null | Key | Default | Extra |+----------+-------------+------+-----+---------+----------------+| id | int(11) | NO | PRI | NULL | auto_increment || name | varchar(15) | NO | | NULL | || sex | varchar(15) | YES | | 中 | || ID_C | varchar(20) | NO | UNI | NULL | || vocation | varchar(8) | YES | | NULL | || salary | float | YES | | 0 | |+----------+-------------+------+-----+---------+----------------+6 rows in set (0.00 sec)mysql>之后我往这张表里面添加了一些数据，从中可以看出我所说的问题
mysql> select * from person_list;+----+-----------+------+--------------------+--------------+---------+| id | name | sex | ID_C | vocation | salary |+----+-----------+------+--------------------+--------------+---------+| 1 | 诸葛亮 | 男 | 360428199908230544 | 蜀国 | 8654.56 || 2 | 关羽 | 男 | 360428198908230544 | 蜀国 | 86.236 || 3 | 貂蝉 | 女 | 361428198908231479 | 美女集团 | 4566.02 || 4 | 西施 | 女 | 795410365478901234 | 美女集团 | 124.1 || 5 | 雷军 | 男 | 469787036544025984 | 小米公司 | 1784.1 || 6 | 乔布斯 | 男 | 456982103749651024 | 苹果公司 | 88888.9 || 7 | 李白 | 中 | 147852036978410210 | NULL | 0 || 10 | 乔布儿 | 男 | 456902103749651024 | 苹果公司 | 88888.9 || 13 | 乔布儿 | 男 | 056902103749651024 | 苹果公司 | 88888.9 |+----+-----------+------+--------------------+--------------+---------+9 rows in set (0.00 sec)mysql>如果我现在再插入一条记录，那么这个新增加的记录的"id"值会是14
mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);Query OK, 1 row affected (0.05 sec)mysql> select * from person_list;+----+-----------+------+--------------------+--------------+---------+| id | name | sex | ID_C | vocation | salary |+----+-----------+------+--------------------+--------------+---------+| 1 | 诸葛亮 | 男 | 360428199908230544 | 蜀国 | 8654.56 || 2 | 关羽 | 男 | 360428198908230544 | 蜀国 | 86.236 || 3 | 貂蝉 | 女 | 361428198908231479 | 美女集团 | 4566.02 || 4 | 西施 | 女 | 795410365478901234 | 美女集团 | 124.1 || 5 | 雷军 | 男 | 469787036544025984 | 小米公司 | 1784.1 || 6 | 乔布斯 | 男 | 456982103749651024 | 苹果公司 | 88888.9 || 7 | 李白 | 中 | 147852036978410210 | NULL | 0 || 10 | 乔布儿 | 男 | 456902103749651024 | 苹果公司 | 88888.9 || 13 | 乔布儿 | 男 | 056902103749651024 | 苹果公司 | 88888.9 || 14 | 马云 | 男 | 444989898784562304 | 淘宝公司 | 54588.9 |+----+-----------+------+--------------------+--------------+---------+10 rows in set (0.00 sec)mysql> 然后我故意输入10条错误的语句（这个表的ID_C值不能重复）mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云","男","444989898784562304","淘宝公司",54588.85124);ERROR 1062 (23000): Duplicate entry '444989898784562304' for key 'ID_C'之后我又增加1条正确的记录，结果发现该新记录的"ID"值是25，最后一条 跟 倒数第二条 的"ID"值刚好是11-1=10mysql> insert into person_list (name,sex,ID_C,vocation,salary) value ("马云的儿子","男","444989898784562305","淘宝公司",54588.85124);Query OK, 1 row affected (0.04 sec)mysql> select * from person_list;+----+-----------------+------+--------------------+--------------+---------+| id | name | sex | ID_C | vocation | salary |+----+-----------------+------+--------------------+--------------+---------+| 1 | 诸葛亮 | 男 | 360428199908230544 | 蜀国 | 8654.56 || 2 | 关羽 | 男 | 360428198908230544 | 蜀国 | 86.236 || 3 | 貂蝉 | 女 | 361428198908231479 | 美女集团 | 4566.02 || 4 | 西施 | 女 | 795410365478901234 | 美女集团 | 124.1 || 5 | 雷军 | 男 | 469787036544025984 | 小米公司 | 1784.1 || 6 | 乔布斯 | 男 | 456982103749651024 | 苹果公司 | 88888.9 || 7 | 李白 | 中 | 147852036978410210 | NULL | 0 || 10 | 乔布儿 | 男 | 456902103749651024 | 苹果公司 | 88888.9 || 13 | 乔布儿 | 男 | 056902103749651024 | 苹果公司 | 88888.9 || 14 | 马云 | 男 | 444989898784562304 | 淘宝公司 | 54588.9 || 25 | 马云的儿子 | 男 | 444989898784562305 | 淘宝公司 | 54588.9 |+----+-----------------+------+--------------------+--------------+---------+11 rows in set (0.00 sec)mysql> 所以我估摸着，在插入记录 语句错误的时候 自动增长类型的值会依旧增加，不是只有正确的时候才会+1。