Syntax:
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,...]

The LOAD DATA INFILE statement reads rows from a text file into a table
at a very high speed. LOAD DATA INFILE is the complement of SELECT ...
INTO OUTFILE. (See
http://dev.mysql.com/doc/refman/5.5/en/select-into.html.) To write data
from a table to a file, use SELECT ... INTO OUTFILE. To read the file
back into a table, use LOAD DATA INFILE. The syntax of the FIELDS and
LINES clauses is the same for both statements. Both clauses are
optional, but FIELDS must precede LINES if both are specified.

You can also load data files by using the mysqlimport utility; it
operates by sending a LOAD DATA INFILE statement to the server. The
--local option causes mysqlimport to read data files from the client
host. You can specify the --compress option to get better performance
over slow networks if the client and server support the compressed
protocol. See http://dev.mysql.com/doc/refman/5.5/en/mysqlimport.html.

For more information about the efficiency of INSERT versus LOAD DATA
INFILE and speeding up LOAD DATA INFILE, see
http://dev.mysql.com/doc/refman/5.5/en/insert-speed.html.

The file name must be given as a literal string. On Windows, specify
backslashes in path names as forward slashes or doubled backslashes.
The character_set_filesystem system variable controls the
interpretation of the file name.

The server uses the character set indicated by the
character_set_database system variable to interpret the information in
the file. SET NAMES and the setting of character_set_client do not
affect interpretation of input. If the contents of the input file use a
character set that differs from the default, it is usually preferable
to specify the character set of the file by using the CHARACTER SET
clause. A character set of binary specifies "no conversion."

LOAD DATA INFILE interprets all fields in the file as having the same
character set, regardless of the data types of the columns into which
field values are loaded. For proper interpretation of file contents,
you must ensure that it was written with the correct character set. For
example, if you write a data file with mysqldump -T or by issuing a
SELECT ... INTO OUTFILE statement in mysql, be sure to use a
--default-character-set option so that output is written in the
character set to be used when the file is loaded with LOAD DATA INFILE.

*Note*: It is not possible to load data files that use the ucs2, utf16,
or utf32 character set.

If you use LOW_PRIORITY, execution of the LOAD DATA statement is
delayed until no other clients are reading from the table. This affects
only storage engines that use only table-level locking (such as MyISAM,
MEMORY, and MERGE).

If you specify CONCURRENT with a MyISAM table that satisfies the
condition for concurrent inserts (that is, it contains no free blocks
in the middle), other threads can retrieve data from the table while
LOAD DATA is executing. This option affects the performance of LOAD
DATA a bit, even if no other thread is using the table at the same
time.

With row-based replication, CONCURRENT is replicated regardless of
MySQL version. With statement-based replication CONCURRENT is not
replicated prior to MySQL 5.5.1 (see Bug #34628). For more information,
see
http://dev.mysql.com/doc/refman/5.5/en/replication-features-load-data.h
tml.

The LOCAL keyword affects expected location of the file and error
handling, as described later. LOCAL works only if your server and your
client both have been configured to permit it. For example, if mysqld
was started with --local-infile=0, LOCAL does not work. See
http://dev.mysql.com/doc/refman/5.5/en/load-data-local.html.

The LOCAL keyword affects where the file is expected to be found:

o If LOCAL is specified, the file is read by the client program on the
  client host and sent to the server. The file can be given as a full
  path name to specify its exact location. If given as a relative path
  name, the name is interpreted relative to the directory in which the
  client program was started.

  When using LOCAL with LOAD DATA, a copy of the file is created in the
  server's temporary directory. This is not the directory determined by
  the value of tmpdir or slave_load_tmpdir, but rather the operating
  system's temporary directory, and is not configurable in the MySQL
  Server. (Typically the system temporary directory is /tmp on Linux
  systems and C:\WINDOWS\TEMP on Windows.) Lack of sufficient space for
  the copy in this directory can cause the LOAD DATA LOCAL statement to
  fail.

o If LOCAL is not specified, the file must be located on the server
  host and is read directly by the server. The server uses the
  following rules to locate the file:

  o If the file name is an absolute path name, the server uses it as
    given.

  o If the file name is a relative path name with one or more leading
    components, the server searches for the file relative to the
    server's data directory.

  o If a file name with no leading components is given, the server
    looks for the file in the database directory of the default
    database.

In the non-LOCAL case, these rules mean that a file named as
./myfile.txt is read from the server's data directory, whereas the file
named as myfile.txt is read from the database directory of the default
database. For example, if db1 is the default database, the following
LOAD DATA statement reads the file data.txt from the database directory
for db1, even though the statement explicitly loads the file into a
table in the db2 database:

LOAD DATA INFILE 'data.txt' INTO TABLE db2.my_table;

For security reasons, when reading text files located on the server,
the files must either reside in the database directory or be readable
by the user account used to run the server. Also, to use LOAD DATA
INFILE on server files, you must have the FILE privilege. See
http://dev.mysql.com/doc/refman/5.5/en/privileges-provided.html. For
non-LOCAL load operations, if the secure_file_priv system variable is
set to a nonempty directory name, the file to be loaded must be located
in that directory.

Using LOCAL is a bit slower than letting the server access the files
directly, because the contents of the file must be sent over the
connection by the client to the server. On the other hand, you do not
need the FILE privilege to load local files.

LOCAL also affects error handling:

o With LOAD DATA INFILE, data-interpretation and duplicate-key errors
  terminate the operation.

o With LOAD DATA LOCAL INFILE, data-interpretation and duplicate-key
  errors become warnings and the operation continues because the server
  has no way to stop transmission of the file in the middle of the
  operation. For duplicate-key errors, this is the same as if IGNORE is
  specified. IGNORE is explained further later in this section.

The REPLACE and IGNORE keywords control handling of input rows that
duplicate existing rows on unique key values:

o If you specify REPLACE, input rows replace existing rows. In other
  words, rows that have the same value for a primary key or unique
  index as an existing row. See [HELP REPLACE].

o If you specify IGNORE, rows that duplicate an existing row on a
  unique key value are discarded.

o If you do not specify either option, the behavior depends on whether
  the LOCAL keyword is specified. Without LOCAL, an error occurs when a
  duplicate key value is found, and the rest of the text file is
  ignored. With LOCAL, the default behavior is the same as if IGNORE is
  specified; this is because the server has no way to stop transmission
  of the file in the middle of the operation.

URL: http://dev.mysql.com/doc/refman/5.5/en/load-data.html

