MySQL学习笔记十一：数据导入与导出

数据导入

1.mysqlimport命令行导入数据

在使用mysqlimport命令导入数据时，数据来源文件名要和目标表一致，不想改文件名的话，可以复制一份创建临时文件，示例如下。

建立一个文本users.txt，内容如下：

1001,张三,[e-mail]
1002,李四,[e-mail]
1003,王五,[e-mail]
1004,李白,[e-mail]

创建一个表users

mysql> create table if not exists users(
    -> id int(11) not null default 1000,
    -> name varchar(50),
    -> email varchar(50)
    -> );
Query OK, 0 rows affected (0.15 sec)

使用mysqlimport将users.txt中数据导入users表

PS F:\> mysqlimport -u root -p123456 zz --default-character-set=gbk --fields-terminated-by=',' f:\users.txt
zz.users: Records: 3  Deleted: 0  Skipped: 0  Warnings: 0
-----------------------------验证----------------------------------
mysql> select * from users\G
*************************** 1. row ***************************
   id: 1003
 name: 王五
email: [e-mail]
*************************** 2. row ***************************
   id: 1001
 name: 张三
email: [e-mail]
*************************** 3. row ***************************
   id: 1002
 name: 李四
email: [e-mail]

分列，使用--fields-terninated-by参数来指定每列的分隔符，例如：

1004#李白#[e-mail]  --文本内容
---------------------------验证----------------------------------
PS F:\> mysqlimport -u root -p7758520 zz  --fields-terminated-by='#' f:\users.txt
zz.users: Records: 1  Deleted: 0  Skipped: 0  Warnings: 0

mysql> select * from users;
+------+------+-------------------+
| id   | name | email             |
+------+------+-------------------+
| 1004 | 李白 | [e-mail] |
+------+------+-------------------+
1 row in set (0.00 sec)

如果列值中出现了分隔符，例如 1004"#李#白"#"[e-mail]"

PS F:\> mysqlimport -u root -p7758520 zz  --fields-terminated-by='#' --fields-enclosed-by=\"  f:\users.txt

如果遇到一条记录有多行，则可以使用--lines-terminated-by=name来指定行的结束符

PS F:\> mysqlimport -u root -p7758520 zz  --fields-terminated-by='#' --fields-enclosed-by=\"  --lines-terminated-by='xxx\n' f:\users.txt

2.使用Load Data语句导入数据

Load Data 语句的使用语法如下：

LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name'
    [REPLACE | IGNORE]
    INTO TABLE tbl_name
    [CHARACTER SET charset_name]
    [{FIELDS | COLUMNS}
        [TERMINATED BY 'string']
        [[OPTIONALLY] ENCLOSED BY 'char']
        [ESCAPED BY 'char']
    ]
    [LINES
        [STARTING BY 'string']
        [TERMINATED BY 'string']
    ]
    [IGNORE number {LINES | ROWS}]
    [(col_name_or_user_var,...)]
    [SET col_name = expr,...]

刚开始看到这个语法吓了一跳，这么长，其实没这么复杂，一般只需记住LOAD DATA INFILE file_name INTO TABLE tb_name这个即可，示例：

首先创建一个表sql_users，利用上面的users表复制一下

mysql> create table sql_users as select * from users;
Query OK, 1 row affected (0.06 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> truncate table sql_users;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from sql_users;
Empty set (0.00 sec)

文本sql_users.txt

1004#李白#[e-mail]
1005#杜牧#[e-mail]
1006#杜甫#[e-mail]
1007#苏轼#[e-mail]

利用LOAD DATA INFILEE语句导入数据

mysql> load data infile 'f:\sql_users.txt' into table sql_users fields terminated by '#';
Query OK, 4 rows affected (0.00 sec)
Records: 4  Deleted: 0  Skipped: 0  Warnings: 0

mysql> select * from sql_users;
+------+------+--------------------+
| id   | name | email              |
+------+------+--------------------+
| 1004 | 李白 | [e-mail]
| 1005 | 杜牧 | [e-mail]
| 1006 | 杜甫 | [e-mail]
| 1007 | 苏轼 | [e-mail]  |
+------+------+--------------------+
4 rows in set (0.00 sec)

如果在导入数据时，遇到字符串无法识别时，一般都是字符集有问题，使用charset选项即可解决

mysql> load data infile 'f:\sql_users.txt' into table sql_users  fields terminated by '#';
ERROR 1366 (HY000): Incorrect string value: '\xC0\xEE\xB0\xD7' for column 'name' at row 1
--------------------------------字符集不一样-----------------------
mysql> load data infile 'f:\sql_users.txt' into table sql_users  character set gbk fields terminated by '#';
Query OK, 4 rows affected (0.03 sec)
Records: 4  Deleted: 0  Skipped: 0  Warnings: 0

LOAD DATA INFILE命令默认要导入数据存放在服务上，如果要导入客户端的数据，可以指定LOCAL，那么mysql将从客户端读取数据，这样的方式会比服务器上操作要慢一点，因为客户端的数据需要通过网络传输到服务器。

mysql> load data local infile 'f:\sql_users.txt' into table sql_users  fields terminated by '#';

如果需要忽略与主键值重复的记录值或者替换重复值，可以使用IGNORE或REPLACE选项，但是LOAD DATA INFILE命令语法中有两处IGNORE关键字，前面一个是用来此功能的，后面一个用来指定需要忽略的前N条记录。

--------------------文本中的内容----------
PS F:\> MORE .\sql_users.txt
1004#李白#[e-mail]
1005#杜牧#[e-mail]
1006#杜甫#[e-mail]
1007#苏轼#[e-mail]
1007#苏轼#[e-mail]
-----------------------导入-------------------
mysql> LOAD DATA INFILE 'F:\sql_users.txt' IGNORE INTO TABLE sql_users CHARACTER SET GBK FIELDS TERMINATED BY '#';
Query OK, 4 rows affected (0.00 sec)
Records: 5  Deleted: 0  Skipped: 1  Warnings: 0

mysql> select * from sql_users;
+------+------+--------------------+
| id   | name | email              |
+------+------+--------------------+
 |1004 | 李白 | [e-mail]
  |005 | 杜牧 | [e-mail]
  |006 | 杜甫 | [e-mail]
 |1007 | 苏轼 | [e-mail]
+------+------+--------------------+
4 rows in set (0.00 sec)

如果不想导入数据文件的前N行，使用IGNORE N LINES来处理

mysql> SELECT * FROM SQL_USERS;
Empty set (0.00 sec)

mysql> LOAD DATA INFILE 'F:\sql_users.txt' IGNORE INTO TABLE sql_users CHARACTER SET GBK FIELDS TERMINATED BY '#' IGNORE
 1 LINES;
Query OK, 3 rows affected (0.00 sec)
Records: 4  Deleted: 0  Skipped: 1  Warnings: 0

mysql> SELECT * FROM SQL_USERS;
+------+------+--------------------+
| id   | name | email              |
+------+------+--------------------+
  |005 | 杜牧 | [e-mail]
  |006 | 杜甫 | [e-mail]
 |1007 | 苏轼 | [e-mail]
+------+------+--------------------+
3 rows in set (0.00 sec)

如果在数据文件中记录行头有某些字符，又不想被导入，可以使用LINES STARTING BY来解决，但是如果某行记录不包含这些字符的话，那么这行记录也会被忽略。

---------------文本----------------
PS F:\> MORE .\sql_users.txt
zzz1004#李白#[e-mail]
1005#杜牧#[e-mail]
zzz1006#杜甫#[e-mail]
1007#苏轼#[e-mail]
zzz1007#苏轼#[e-mail]
---------------验证-----------------------
mysql> select * from sql_users;
Empty set (0.00 sec)

mysql> LOAD DATA INFILE 'F:\sql_users.txt' IGNORE INTO TABLE sql_users CHARACTER SET GBK FIELDS TERMINATED BY '#' LINES
STARTING BY 'zzz';
Query OK, 3 rows affected (0.00 sec)
Records: 3  Deleted: 0  Skipped: 0  Warnings: 0

mysql> select * from sql_users;
+------+------+--------------------+
| id   | name | email              |
+------+------+--------------------+
 |1004 | 李白 | [e-mail]
  |006 | 杜甫 | [e-mail]
| 1007 | 苏轼 | [e-mail]  |
+------+------+--------------------+
3 rows in set (0.00 sec)

数据文件为Excel文件的处理，首先将Excel文件保存为CSV格式，这样字段间都是用逗号隔开的，再进行处理。

-----------excel转换成CSV的数据-------------
PS F:\> MORE .\stu.csv
学号,姓名,班级
4010404,祝小贤,A1012
4010405,肖小杰,A1013
4010406,钟小喜,A1014
4010407,钟小惠,A1015
--------------------进行导入--------------------
mysql> CREATE TABLE stu(
    -> sno int not null primary key,
    -> sname varchar(30),
    ->  class char(6)
    -> );
Query OK, 0 rows affected (0.05 sec)

mysql> LOAD DATA INFILE 'F:\stu.csv' INTO TABLE stu CHARACTER SET GBK FIELDS TERMINATED BY ',' IGNORE 1 LINES;
Query OK, 4 rows affected (0.00 sec)
Records: 4  Deleted: 0  Skipped: 0  Warnings: 0

mysql> SELECT * FROM STU;
+---------+--------+--------+
| sno     | sname  | class  |
+---------+--------+--------+
 |4010404 | 祝小贤 | A1012
 |4010405 | 肖小杰 | A1013
 |4010406 | 钟小喜 | A1014
 |4010407 | 钟小惠 | A1015
+---------+--------+--------+
4 rows in set (0.00 sec)

数据文件列值中有特殊符号，使用enclosed by来处理。例如，列值中有分隔符

---------------------文本--------------------
PS F:\> MORE .\stu.csv
学号,姓名,班级
4010404,祝小贤,"A1012,01"
4010405,肖小杰,"A1013,02"
4010406,钟小喜,"A1014,03"
4010407,钟小惠,"A1015,04"
--------------------导入------------------------
mysql> select * from stu;
Empty set (0.00 sec)

mysql> LOAD DATA INFILE 'F:\stu.csv' INTO TABLE stu CHARACTER SET GBK FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TER
MINATED BY '\r\n' IGNORE 1 LINES;
Query OK, 4 rows affected (0.01 sec)
Records: 4  Deleted: 0  Skipped: 0  Warnings: 0

mysql> select * from stu;
+---------+--------+----------+
| sno     | sname  | class    |
+---------+--------+----------+
| 4010404 | 祝小贤 | A1012,01 |
| 4010405 | 肖小杰 | A1013,02 |
| 4010406 | 钟小喜 | A1014,03 |
| 4010407 | 钟小惠 | A1015,04 |
+---------+--------+----------+
4 rows in set (0.00 sec)

数据导入时换行符的问题，在上面的示例中，有几个数据导入到表中后，查询时结果显示有点别扭，不知大家注意到了没。

在Windows系统中，文本格式的换行符有"\r+\n"组成，而在linux系统中，换行符是"\n"。因此出出现上述问题，解决方法就是指定换行符LINES TERMINATED BY。

mysql> LOAD DATA INFILE 'F:\stu.csv' INTO TABLE stu CHARACTER SET GBK FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY '\r\n' IGNORE 1 LINES;

表的列数多余数据文件中的列数，解决方法就是指定要导入到表的字段，如下所示

mysql> desc stu;       --查看表结构
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| sno   | int(11)     | NO   | PRI | NULL    |       |
| sname | varchar(30) | YES  |     | NULL    |       |
| class | varchar(20) | YES  |     | NULL    |       |
| age   | int(11)     | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
---------------------导入数据-------------------
mysql> LOAD DATA INFILE 'F:\stu.csv' INTO TABLE stu CHARACTER SET GBK FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TER
MINATED BY '\r\n' IGNORE 1 LINES (SNO,SNAME,CLASS);
Query OK, 4 rows affected (0.00 sec)
Records: 4  Deleted: 0  Skipped: 0  Warnings: 0

mysql> SELECT * FROM STU;
+---------+--------+-------+------+
| sno     | sname  | class | age  |
+---------+--------+-------+------+
| 4010404 | 祝小贤 | A1012 | NULL |
| 4010405 | 肖小杰 | A1013 | NULL |
| 4010406 | 钟小喜 | A1014 | NULL |
| 4010407 | 钟小惠 | A1015 | NULL |
+---------+--------+-------+------+
4 rows in set (0.00 sec)

如果是表的列数少于数据文件中的列数呢，解决办法可以指定用户变量来接收多余的列值，如下

-------------------文本数据-------------------------
PS F:\> MORE .\stu.csv
学号,姓名,班级
4010404,祝小贤,"A1012",20,male
4010405,肖小杰,"A1013",22,female
4010406,钟小喜,"A1014",24,male
4010407,钟小惠,"A1015",26,female
------------------导入-----------------------------
mysql> LOAD DATA INFILE 'F:\stu.csv' INTO TABLE stu CHARACTER SET GBK FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TER
MINATED BY '\r\n' IGNORE 1 LINES (SNO,SNAME,CLASS,AGE,@GENDER);
Query OK, 4 rows affected (0.05 sec)
Records: 4  Deleted: 0  Skipped: 0  Warnings: 0

mysql> SELECT * FROM STU;
+---------+--------+-------+------+
| sno     | sname  | class | age  |
+---------+--------+-------+------+
| 4010404 | 祝小贤 | A1012 |   20 |
| 4010405 | 肖小杰 | A1013 |   22 |
| 4010406 | 钟小喜 | A1014 |   24 |
| 4010407 | 钟小惠 | A1015 |   26 |
+---------+--------+-------+------+
4 rows in set (0.00 sec)

如果表的列数与数据文件的不同，且某些字段类型都不一致，那怎么解决呢？方法如下：

------------------文本----------------------
PS F:\> MORE .\stu.csv
学号,姓名,班级
4010404,祝小贤,"A1012",20,male,信息学院
4010405,肖小杰,"A1013",22,female,外院
4010406,钟小喜,"A1014",24,male,会计学院
4010407,钟小惠,"A1015",26,female,商学院
--------------------处理-------------------------
mysql> desc stu;   //表结构
+--------+-------------+------+-----+---------+-------+
| Field  | Type        | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| sno    | int(11)     | NO   | PRI | NULL    |       |
| sname  | varchar(30) | YES  |     | NULL    |       |
| class  | varchar(20) | YES  |     | NULL    |       |
| age    | int(11)     | YES  |     | NULL    |       |
| gender | tinyint(4)  | YES  |     | NULL    |       |
+--------+-------------+------+-----+---------+-------+
5 rows in set (0.01 sec)

mysql> LOAD DATA INFILE 'F:\stu.csv' INTO TABLE stu CHARACTER SET GBK FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TER
MINATED BY '\r\n' IGNORE 1 LINES (SNO,SNAME,CLASS,AGE,@GENDER,@x) SET GENDER=IF(@GENDER='MALE',1,0);
Query OK, 4 rows affected (0.09 sec)
Records: 4  Deleted: 0  Skipped: 0  Warnings: 0

mysql> SELECT * FROM STU;
+---------+--------+-------+------+--------+
| sno     | sname  | class | age  | gender |
+---------+--------+-------+------+--------+
| 4010404 | 祝小贤 | A1012 |   20 |      1 |
| 4010405 | 肖小杰 | A1013 |   22 |      0 |
| 4010406 | 钟小喜 | A1014 |   24 |      1 |
| 4010407 | 钟小惠 | A1015 |   26 |      0 |
+---------+--------+-------+------+--------+
4 rows in set (0.00 sec)

数据导出

数据导出比较简单，只要会SELECT ...INTO OUTFILE语句即可，例如

mysql> SELECT * FROM STU INTO OUTFILE "F:\stu_bak.txt"  CHARACTER SET GBK FIELDS TERMINATED BY '##' LINES TERMINATED BY'\r\n';
Query OK, 4 rows affected (0.00 sec)
-------------------------------stu_bak.txt-----------------------
PS F:\> MORE .\stu_bak.txt
4010404##祝小贤##A1012##20##1
4010405##肖小杰##A1013##22##0
4010406##钟小喜##A1014##24##1
4010407##钟小惠##A1015##26##0

还有一个SELECT...INTO DUMPFILE，这个语句也是将数据导出到文件，但是不能格式化语句，如FIELDS,LINES这些，它是将数据原汁原味输出到文件。但是只能输出一个记录，用处不大。