not in 效率太低
所以用left join来处理

SELECT id FROM `fa_user` AS A LEFT JOIN
(SELECT user_id as i FROM `fa_third`) AS B ON A.id=B.i
WHERE B.i IS NULL

问题

早上到公司同时说数据库的表丢了，上去一看确实丢了，由于断过一次电，怀疑断电导致的，但是一想想断电出现的问题就不止只丢失一个表的事啊，先看一下日志和同时反馈的问题。
同时直接给我发了这样的一条消息：
Table './we7_71yunduan_to/ims_mc_members' is marked as crashed and should be repaired
那就检查一下这个表具体的问题！

解决方法

mysql> use we7_71yunduan_to
Database changed
mysql> check table ims_mc_members
    -> ;
+---------------------------------+-------+----------+----------------------------------------------------------------+
| Table                           | Op    | Msg_type | Msg_text                                                       |
+---------------------------------+-------+----------+----------------------------------------------------------------+
| we7_71yunduan_to.ims_mc_members | check | warning  | Table is marked as crashed                                     |
| we7_71yunduan_to.ims_mc_members | check | warning  | 1 client is using or hasn't closed the table properly          |
| we7_71yunduan_to.ims_mc_members | check | error    | Found key at page 26624 that points to record outside datafile |
| we7_71yunduan_to.ims_mc_members | check | error    | Corrupt                                                        |
+---------------------------------+-------+----------+----------------------------------------------------------------+
4 rows in set (0.04 sec)

mysql> repair table ims_mc_members
    -> ;
+---------------------------------+--------+----------+----------------------------------------------+
| Table                           | Op     | Msg_type | Msg_text                                     |
+---------------------------------+--------+----------+----------------------------------------------+
| we7_71yunduan_to.ims_mc_members | repair | info     | Wrong bytesec:   0-  0-  0 at 70372; Skipped |
| we7_71yunduan_to.ims_mc_members | repair | warning  | Number of rows changed from 243 to 242       |
| we7_71yunduan_to.ims_mc_members | repair | status   | OK                                           |
+---------------------------------+--------+----------+----------------------------------------------+
3 rows in set (0.11 sec)

mysql> check table ims_mc_members;
+---------------------------------+-------+----------+----------+
| Table                           | Op    | Msg_type | Msg_text |
+---------------------------------+-------+----------+----------+
| we7_71yunduan_to.ims_mc_members | check | status   | OK       |
+---------------------------------+-------+----------+----------+
1 row in set (0.00 sec)

mysql>

在处理过程发现表有两个警告和两个错误：表崩了，表被占着或关的姿势不对。。。。
处理方法就是repair table ims_mc_members
最后再检查一下问题结局

1、检查并修改mysql的my.ini的配置文件

default-character-set=utf8

2、建立数据库是要指定字符集

create database mydb default character set utf8 collate utf8_general_ci;

3、建立数据表示也要指定字符集：
出问题的命令：

CREATE TABLE IF NOT EXISTS `mydb` (
  `id` varchar(64) NOT NULL,
  `name` int(11) NOT NULL,
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1;

正确的命令：

CREATE TABLE IF NOT EXISTS `mydb` (
 `id` varchar(64) NOT NULL,
 `name` int(11) NOT NULL,
) ENGINE=InnoDB DEFAULT CHARSET=utf8;