php mysql 查询表中AUTO_INCREMENT字段名称

desc 表名 ;
然后循环取字段名和属性，判断哪个是主键 Key=='PRI'为主键

mysql> desc cdb_videos;
+--------------+-----------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+-----------------------+------+-----+---------+-------+
| vid | varchar(16) | NO | PRI | | |
| uid | mediumint(8) unsigned | NO | | 0 | |
| dateline | int(10) unsigned | NO | MUL | 0 | |
| displayorder | tinyint(3) | NO | MUL | 0 | |
| tid | mediumint(8) unsigned | NO | | 0 | |
| pid | int(10) unsigned | NO | | 0 | |
| vtype | tinyint(1) unsigned | NO | | 0 | |
| vview | mediumint(8) unsigned | NO | | 0 | |
| vtime | smallint(6) unsigned | NO | | 0 | |
| visup | tinyint(1) unsigned | NO | | 0 | |
| vthumb | varchar(128) | NO | | | |
| vtitle | varchar(64) | NO | | | |
| vclass | varchar(32) | NO | | | |
| vautoplay | tinyint(1) | NO | | 0 | |
+--------------+-----------------------+------+-----+---------+-------+