mysql操作命令master-to-master 1.select語句中把兩個字符串字段合並成一個字段： select concat(a, b) as c from tables 2.按日期分組查詢 select DATE_FORMAT( created_at, '%Y-%m-%d %H' ) as t from tables group by t 3.mysql創建用戶/添加遠程/修改用戶密碼 先進入mysql命令：mysql -uroot -proot ->create user username@'192.168.39.%' IDENTIFIED BY 'password'; 配置遠程 ->GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO username@'192.168.39.%' IDENTIFIED BY 'password'; 修改密碼 ->update mysql.user set password=PASSWORD('xxx') where user='username'; ->flush privileges; 4.master-to-master 先配置遠程： GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO username@'192.168.39.%' IDENTIFIED BY 'password'; 建立master: ->slave stop; ->change master to master_host='192.168.0.2', ->master_user='backup', ->master_password='back', ->master_log_file='mysql-bin.000001', ->master_log_pos=106; ->slave start; ->show slave status\G 4.查看server_id，注意master-to-master時，兩個服務器的server_id不能一樣，需要修改。 ->show variables like 'server_id'; 修改server_id ->set global server_id=10; 5.查看auto_increment_increment與auto_increment_offset值: ->SHOW VARIABLES LIKE 'auto_inc%'; 6.兩個服務器master-to-master，必須設置auto_increment_offset值為不同，如下： 第一台： auto_increment_increment =2 #為開始值 auto_increment_offset = 1 第二台： auto_increment_increment =2 #為開始值 auto_increment_offset = 2 7.mysql遠程鏈接權限有以下14個： select,insert,update,delete,create,drop,index,alter,grant,references,reload,shutdown,process,file
