MySQL数据导入导出（用于个人学习与回顾）

该实例将练习MySQL的导入导出操作

实例：

1. 将/etc/passwd文件导入userdb库user表并给每条记录加编号

2. 将userdb库user表中UID小于100的前10条记录导出，存为/mydata/user1.txt文件

• 新建userdb库，切换到userdb库，并且设置如下字段；

mysql> create database userdb;Query OK, 1 row affected (0.00 sec)mysql> use userdb;Database changedmysql> create table user(    -> username varchar(24) not null,    -> password varchar(48) default 'x',    -> uid int(5) not null,    -> gid int(5) not null,    -> fullname varchar(48),    -> homedir varchar(64) not null,    -> shell varchar(24) not null    -> );Query OK, 0 rows affected (0.01 sec)mysql> desc user;+----------+-------------+------+-----+---------+-------+| Field    | Type        | Null | Key | Default | Extra |+----------+-------------+------+-----+---------+-------+| username | varchar(24) | NO   |     | NULL    |       || password | varchar(48) | YES  |     | x       |       || uid      | int(5)      | NO   |     | NULL    |       || gid      | int(5)      | NO   |     | NULL    |       || fullname | varchar(48) | YES  |     | NULL    |       || homedir  | varchar(64) | NO   |     | NULL    |       || shell    | varchar(24) | NO   |     | NULL    |       |+----------+-------------+------+-----+---------+-------+7 rows in set (0.01 sec)

• 注：在MySQL 5.7.6版本之后，导入文件只能在secure_file_priv指定的文件夹下。如果直接导入会报错。执行show variables like '%secure%'命令显示文件目录：

mysql> load data infile '/etc/passwd' into table user fields terminated by ':';ERROR 1290 (HY000): The MySQL server is running with the --secure-file-priv option so it cannot execute this statementmysql> show variables like '%secure%';+--------------------------+-----------------------+| Variable_name            | Value                 |+--------------------------+-----------------------+| require_secure_transport | OFF                   || secure_auth              | ON                    || secure_file_priv         | /var/lib/mysql-files/ |+--------------------------+-----------------------+3 rows in set (0.00 sec)

• 执行导入操作

-将/etc/passwd文件复制到/var/lib/mysql-files/目录下，

-读取/var/lib/mysql-files/passwd文件内容，以":"为分隔，导入到user表中：

[root@host50 ~]#cp /etc/passwd /var/lib/mysql-files/mysql> LOAD DATA INFILE '/var/lib/mysql-files/passwd'-> INTO TABLE user-> FIELDS TERMINATED BY ':';Query OK, 42 rows affected (0.11 sec)Records: 42  Deleted: 0  Skipped: 0  Warnings: 0

注：上述操作中省略了行分隔 LINES TERMINATED BY '\n'，因为这是默认的情况（每行一条原始记录），除非需要以其他字符分割行，才需要用到这个。

• 确认导入结果

mysql> select count(*) from user;+----------+| count(*) |+----------+|       42 |+----------+1 row in set (0.00 sec)mysql> select * from user limit 10;+----------+----------+-----+-----+----------+-----------------+----------------+| username | password | uid | gid | fullname | homedir         | shell          |+----------+----------+-----+-----+----------+-----------------+----------------+| root     | x        |   0 |   0 | root     | /root           | /bin/bash      || bin      | x        |   1 |   1 | bin      | /bin            | /sbin/nologin  || daemon   | x        |   2 |   2 | daemon   | /sbin           | /sbin/nologin  || adm      | x        |   3 |   4 | adm      | /var/adm        | /sbin/nologin  || lp       | x        |   4 |   7 | lp       | /var/spool/lpd  | /sbin/nologin  || sync     | x        |   5 |   0 | sync     | /sbin           | /bin/sync      || shutdown | x        |   6 |   0 | shutdown | /sbin           | /sbin/shutdown || halt     | x        |   7 |   0 | halt     | /sbin           | /sbin/halt     || mail     | x        |   8 |  12 | mail     | /var/spool/mail | /sbin/nologin  || operator | x        |  11 |   0 | operator | /root           | /sbin/nologin  |+----------+----------+-----+-----+----------+-----------------+----------------+10 rows in set (0.00 sec)

• 为user表中的每条记录添加自动编号，并验证自动编写结果

mysql> alter table user add sn int(4) auto_increment primary key first;Query OK, 0 rows affected (0.03 sec)Records: 0  Duplicates: 0  Warnings: 0mysql> select * from user limit 10;+----+----------+----------+-----+-----+----------+-----------------+----------------+| sn | username | password | uid | gid | fullname | homedir         | shell          |+----+----------+----------+-----+-----+----------+-----------------+----------------+|  1 | root     | x        |   0 |   0 | root     | /root           | /bin/bash      ||  2 | bin      | x        |   1 |   1 | bin      | /bin            | /sbin/nologin  ||  3 | daemon   | x        |   2 |   2 | daemon   | /sbin           | /sbin/nologin  ||  4 | adm      | x        |   3 |   4 | adm      | /var/adm        | /sbin/nologin  ||  5 | lp       | x        |   4 |   7 | lp       | /var/spool/lpd  | /sbin/nologin  ||  6 | sync     | x        |   5 |   0 | sync     | /sbin           | /bin/sync      ||  7 | shutdown | x        |   6 |   0 | shutdown | /sbin           | /sbin/shutdown ||  8 | halt     | x        |   7 |   0 | halt     | /sbin           | /sbin/halt     ||  9 | mail     | x        |   8 |  12 | mail     | /var/spool/mail | /sbin/nologin  || 10 | operator | x        |  11 |   0 | operator | /root           | /sbin/nologin  |+----+----------+----------+-----+-----+----------+-----------------+----------------+10 rows in set (0.00 sec)

• 从MySQL数据库中导出查询结果

-以将userdb库user表中UID小于100的前10条记录导出为/myload/user2.txt文件为例

首先，修改配置文件中存放导出导入目录及查看修改结果

[root@host50 ~]# mkdir  /myload  ;  chown  mysql  /myload[root@host50 ~]# vim  /etc/my.cnf[mysqld]secure_file_priv="/myload"[root@dbsvr1 ~]# systemctl  restart mysqldmysql> show variables like "secure_file_priv";+------------------+----------+| Variable_name    | Value       |+------------------+----------+| secure_file_priv   | /myload/ |

导出user表中UID小于100的前十条记录

mysql> select * from userdb.user where uid<100    -> into outfile '/myload/user.txt'    -> fields terminated by ":";Query OK, 26 rows affected (0.00 sec)

确认导出结果

[root@host50 ~]# wc -l /myload/user.txt26 /myload/user.txt[root@host50 ~]# tail /myload/user.txt 25:tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin29:rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin33:gdm:x:42:42::/var/lib/gdm:/sbin/nologin35:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin36:avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin37:postfix:x:89:89::/var/spool/postfix:/sbin/nologin38:ntp:x:38:38::/etc/ntp:/sbin/nologin39:tcpdump:x:72:72::/:/sbin/nologin41:apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin42:mysql:x:27:27:MySQL Server:/var/lib/mysql:/bin/false