MySQL 之 LOAD DATA INFILE 快速导入数据

MySQL 之 LOAD DATA INFILE 快速导入数据

SELECT INTO OUTFILE

> help select;
Name: 'SELECT'
Description:
Syntax:
SELECT
[ALL | DISTINCT | DISTINCTROW ]
[HIGH_PRIORITY]
[MAX_STATEMENT_TIME = N]
[STRAIGHT_JOIN]
[SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
[SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]
select_expr [, select_expr ...]
[FROM table_references
[PARTITION partition_list]
[WHERE where_condition]
[GROUP BY {col_name | expr | position}
[ASC | DESC], ... [WITH ROLLUP]]
[HAVING where_condition]
[ORDER BY {col_name | expr | position}
[ASC | DESC], ...]
[LIMIT {[offset,] row_count | row_count OFFSET offset}]
[PROCEDURE procedure_name(argument_list)]
[INTO OUTFILE 'file_name'
[CHARACTER SET charset_name]
export_options
| INTO DUMPFILE 'file_name'
| INTO var_name [, var_name]]
[FOR UPDATE | LOCK IN SHARE MODE]]

举例：

> select * from e;
+------+-------+-------+
| id   | fname | lname |
+------+-------+-------+
| 1669 | Jim   | Smith |
|  337 | Mary  | Jones |
| 2005 | Linda | Black |
+------+-------+-------+

> select * from e into outfile "/data/mysql/e.sql";
或
> select * into outfile "/data/mysql/e.sql" from e;
# cat e.sql
1669    Jim     Smith
337     Mary    Jones
2005    Linda   Black

可以看到，select...into outfile 的结果只包含了表数据，默认以 Tab 分隔，也可指定分隔符：

> select * from e into outfile "/data/mysql/e.sql" fields terminated by ',';
# cat  e.sql
1669,Jim,Smith
337,Mary,Jones
2005,Linda,Black

注意：outfile '/path/file'，中的 path 需要有mysql的权限，否则会报错：

> select * from t into outfile "/root/backup/mysql/t.sql";
ERROR 1 (HY000): Can't create/write to file '/root/backup/mysql/t.sql' (Errcode: 13 - Permission denied)

 回到顶部

LOAD DATA INFILE

LOAD DATA INFILE 语句以非常高的速度从文本文件中读取行到表中。

LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name'
[REPLACE | IGNORE]
INTO TABLE tbl_name
[PARTITION (partition_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_nam
cf3e
e_or_user_var,...)]
[SET col_name = expr,...]

举例：

> delete from e;
> load data infile "/data/mysql/e.sql" into table e fields terminated by ',';
Query OK, 3 rows affected (0.01 sec)
Records: 3  Deleted: 0  Skipped: 0  Warnings: 0

> select * from e;
+------+-------+-------+
| id   | fname | lname |
+------+-------+-------+
| 1669 | Jim   | Smith |
|  337 | Mary  | Jones |
| 2005 | Linda | Black |
+------+-------+-------+

因为我们前面指定的分隔符是 ','，load data 时也要指定分隔符，否则也会报错：

> load data infile "/data/mysql/e.sql" into table e;
ERROR 1265 (01000): Data truncated for column 'id' at row 1

 如果数据被某种符号封闭着，需要指定 ‘ fields enclosed by ’ ：

# cat e.sql
"1669"  "Jim"   "Smith"

　> load data infile "/data/mysql/e.sql" into table e;
　ERROR 1366 (HY000): Incorrect integer value: '"1669"' for column 'id' at row 1　> load data infile "/data/mysql/e.sql" into table e fields enclosed by '"'; 
　Query OK, 1 row affected (0.01 sec)
　Records: 1 Deleted: 0 Skipped: 0 Warnings: 0
如上所示，数据被双引号封闭着，如果直接执行，会报错。另外还有一些格式上的限制，如 LINES TERMINATED BY 'string' ，指定 file 的换行符，如 ‘\n’ 。 回到顶部

mysqlimport

mysql 命令中有 load data ，mysql还有一个可执行文件 mysqlimport，这两个命令可以从文件中把格式化的数据导入数据库，如果有一个包含大数据量的文件，可以实现快速的数据导入。mysqlimport 可以看做是为 LOAD DATA INFILE SQL语句提供了一个命令行界面，他们大部分的参数选项是一致的，由 SELECT into outfile 导出的文件，也可以由 mysqlimport 导入。mysqlimport 需要的文件格式与 load data 差不多，有兴趣的同学可以去研究一下。这里给出它的基本语法：

mysqlimport -u root -pPassword [--local] dbname filename.txt [OPTION]

其中，“Password”参数是root用户的密码，必须与-p选项紧挨着；“--local”是在本地计算机中查找文本文件时使用的（指定 --local 后，文本文件可以放在任何地方进行导入，否则只能放在mysql的data目录下）；“dbname”参数表示数据库的名称；“filename.txt”参数指定了文本文件的路径和称，文件里的数据插入到文件名去掉后缀后剩余名字对应的表中；“OPTION”为可选参数选项，其常见的取值有：--fields-terminated-by=字符串：设置字符串为字段之间的分隔符，可以为单个或多个字符。默认值为制表符“\t”。--fields-enclosed-by=字符：设置字符来括住字段的值，只能为单个字符。--fields-optionally-enclosed-by=字符：设置字符括住CHAR、VARCHAR和TEXT等字符型字段，只能为单个字符。--fields-escaped-by=字符：设置转义字符，默认值为反斜线“\”。--lines-terminated-by=字符串：设置每行数据结尾的字符，可以为单个或多个字符，默认值为“\n”。--ignore-lines=n：表示可以忽略前n行。