MySQL常用命令用法总结

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1. mysqldump 命令的使用

备份和导出数据库

  mysqldump -h database_ip -u Username -p --opt databasename > backup-file.sql

只导出数据库表结构

  mysqldump -h database_ip -d -u Username -p databasename >database_structure.sql

只导出数据库中的某个表

  mysqldump --opt --add-drop-table -u Username -p  databasename tablename > dump.sql

如果不想手工输入密码请使用–password 参数

  mysqldump -h database_ip -u Username --password=123456 --opt databasename > backup-file.sql  mysqldump -h database_ip -d -u Username --password=123456 databasename >database_structure.sql

2. mysql 命令使用

将查询结果保存到文件

  select title from book into outfile '/tmp/outfile.txt';

查找表中多余的重复记录，重复记录是根据某个字段（peopleId）来判断

  select * from people where peopleId in (select  peopleId  from  people  group  by    peopleId  having  count(peopleId) > 1);

查询表中不重复记录(排除重复记录)

  select * from phome_ecms_wma where title in (select distinct title from phome_ecms_wma);

删除表中重复记录,重复记录是根据某个字段（title）来判断

  select *,count(distinct title) INTO OUTFILE '/tmp/table.bak' from phome_ecms_wma group by title;  delete from phome_ecms_wma;  LOAD DATA INFILE '/tmp/table.bak' REPLACE INTO TABLE phome_ecms_wma  character set utf8;

查询数据库当前编码

  mysql> show variables like "character_set%";

修改表字段类型

  mysql> alter table  table_name change last_action last_action datetime NOT NULL default '0000-00-00 00:00:00';

给表添加一个新字段

  mysql> ALTER TABLE host ADD ks_mac VARCHAR(100);

从表中删除一个字段

  mysql> ALTER TABLE table_name DROP field_name;

重命名表
```
  mysql>alter table t1 rename t2;
```

给字段加索引

  mysql> alter table tablename add index 索引名 (字段名1[，字段名2 …]);  mysql> alter table tablename add index emp_name (name);

加主关键字的索引

  mysql> alter table tablename add primary key(id);

加唯一限制条件的索引

  mysql> alter table tablename add unique emp_name2(cardnumber);

删除某个索引

  mysql>alter table tablename drop index emp_name;

远程访问mysql 设置

  mysql> GRANT ALL PRIVILEGES ON database_test.* to root@192.168.1.9  IDENTIFIED BY '123456';  mysql> FLUSH PRIVILEGES;

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