MySQL備忘錄

一、插入數據亂碼：Incorrect string value: '\xE6\x9B\xB9\xE5\x86\xAC...' for column 'realname' at r
1、alter database team_club character set utf8;
2、alter table activity convert to character set utf8
3、alter table tableName character set utf8;
4、alter database databaseName character set utf8;

二、忘記root密碼
# vi /etc/my.cnf
在[mysqld]的段中加上一句：skip-grant-tables
# /etc/init.d/mysqld restart
# /usr/bin/mysql
mysql> USE mysql ;
mysql> UPDATE user SET Password = password ( 'new-password' ) WHERE User = 'root' ;

三、備份數據庫
mysqldump -p regression_testing > re_2010_11_12.sql

四、取消導入數據時候的主外鍵檢查
SET FOREIGN_KEY_CHECKS = 0;

五、取消導入數據時候的主外鍵檢查
SET FOREIGN_KEY_CHECKS = 0;

六、創建數據庫
CREATE DATABASE IF NOT EXISTS ctnefacade default charset utf8 COLLATE utf8_general_cs;
CREATE DATA

七、導入數據
mysql -u username -p -h localhost --default-character-set=utf8 database-name < import.sql

八、.授權
grant all privileges on *.* to `root`@`dev.shtianxin.com` identified by '/;p0.lo9' with grant option;

九、修改字段類型
ALTER TABLE project MODIFY COLUMN manager_assortment VARCHAR(10);

十、修改mysql控制檯亂碼問題
show variables like 'character_set%';
// 控制從命令行sql語句輸入編碼
set global character_set_client='utf8';
// 控制結果集編碼
set global character_set_results='utf8';

十一、修改字段類型
ALTER TABLE member MODIFY summary TEXT;

十二 、安裝、自啓動
yum -y install mysql-server
/etc/rc.d/init.d/mysqld start
chkconfig mysqld on
chkconfig --list mysqld
如果2--5爲on的狀態就OK
#mysqld 0:off 1:off 2:on 3:on 4:on 5:on 6:off

十三、遠程訪問
開放防火牆的端口號
mysql增加權限：mysql庫中的user表新增一條記錄host爲"% "，user爲"root "

十四、重要目錄
數據庫目錄：/var/lib/mysql/
配置文件：/usr/share /mysql（mysql.server命令及配置文件）
相關命令：/usr/bin（mysqladmin mysqldump等命令）
啓動腳本：/etc/rc.d/init.d/（啓動腳本文件mysql的目錄）

十五、卸載
1、rpm -ivh mysql-server-5.1.... --nodeps --force(直接強制安裝)
2、yum remove mysql(rhel卸載)
3、CentOS自帶卸載異常，rpm -e --nodeps mysql-libs-5.1.....
4、server/client都需要安裝
5、卸載自帶mysql，yum remove mysql-libs-5.1....
6、查找以前是否裝有mysql命令：rpm -qa|grep -i mysql

十六、聯合唯一索引（執行時，可刪除重複記錄，剩一條）：
alter ignore table zqw_score_call_back add unique index(userid,adid,package_name);

十七、查詢個人排名
select * FROM
 (
     SELECT A.*,@rank:=@rank+1 as client_ip
     FROM
     (
      SELECT openid as openid,gameid as gameid,subscribe as subscribe,avg(score) as score,create_time as time FROM wx_game_ranking
               where gameid = #{gameid} and subscribe = #{subscribe}
               GROUP BY openid
       ORDER BY score  DESC,  create_time asc
     ) A ,(SELECT @rank:=0) B
 ) M
 where m.openid = #{openid}
ORDER BY score desc

十八、級聯刪除
delete ww from wx_game_winning as ww,wx_game_ranking as rr where ww.ranking_id=rr.id and rr.gameid = #{gameid}

十九、更改編碼
set @@character_set_database='utf8';

二十、自動備份
1：賦予腳步可執行權限
chmod +x mysql_backup.sh
2：添加定時執行計劃
vi /etc/crontab
添加：00 5 * * * root /backup/mysql_backup.sh 每日5點鐘備份一次數據庫

二十一、添加唯一索引

alter table bcd_qrcodeitem add unique index(seqno);