//修改最后一条记录
UPDATE userinfo set userid=\'55\' WHERE 1 ORDER BY userid DESC LIMIT 1
//删除第一条记录
delete from userinfo where 1 order by userid limit 1
mysql sql 修改表名 建立外键 修改列名 删除列 --重命名表
rename table t_softwareport to software_port;
--建立外键
alter table software_port add constraint fk_software_port_softwareprocessid foreign key (softwareprocessid)
references software_process (id) on delete restrict on update restrict;
--删除列
alter table software_type
drop column upid,
drop column orderid;
--修改列名
alter table software_process change software_id softwareid int(11) not null;