如何修改mysql主键的值为自增

CREATE TABLE `t2` (

  `code` varchar(100) DEFAULT NULL,

) ENGINE=InnoDB DEFAULT CHARSET=utf8

-- 添加主键

ALTER TABLE `t2` ADD COLUMN `ID`  int(10) NOT NULL AUTO_INCREMENT AFTER `code`,ADD PRIMARY KEY (`id`)

[你的数据库]

go

create

trigger

name

on

[table]

after

delete

as

begin

--定义游标，使你逐个往下找个ID，并执行update修改

declare

@flag

int

select

@flag=ID

from

deleted

declare

[cursorname]

cursor

for

select

ID

from

[table]

where

ID>@flag

open

[cursorname]

fetch

next

from

[cursorname]

update

[table]

set

ID=ID+1

where

ID=fetch

next

from

[cursorname]

WHILE

@@FETCH_STATUS

=

0

begin

update

[table]

set

ID=ID+1

where

ID=fetch

next

from

[cursorname]

close

[cursorname]

DEALLOCATE

authors_cursor

end

end