The SELECT ... INTO OUTFILE '
file_name' form of
SELECT writes the selected rows to a file. The file is created on the server host, so you must have the
FILE privilege to use this syntax.
file_name cannot be an existing file, which among other things prevents files such as /etc/passwd and database tables from being destroyed. As of MySQL 5.0.19, the
character_set_filesystem system variable controls the interpretation of the file name. The
SELECT ... INTO OUTFILE statement is intended primarily to let you very quickly dump a table to a text file on the server machine. If you want to create the resulting file on some client host other than the server host, you cannot use
SELECT ... INTO OUTFILE. In that case, you should instead use a command such as mysql -e "SELECT ..." >
file_name to generate the file on the client host.
SELECT ... INTO OUTFILE is the complement of
LOAD DATA INFILE. Column values are dumped using the binary character set. In effect, there is no character set conversion. If a table contains columns in several character sets, the output data file will as well and you may not be able to reload the file correctly.
The syntax for the
export_options part of the statement consists of the same FIELDS and LINES clauses that are used with the
LOAD DATA INFILE statement. See
Section 12.2.6, “LOAD DATA INFILE Syntax”, for information about the FIELDS and LINES clauses, including their default values and allowable values.
FIELDS ESCAPED BY controls how to write special characters. If the FIELDS ESCAPED BY character is not empty, it is used as a prefix that precedes following characters on output:
- The FIELDS ESCAPED BY character
- The FIELDS [OPTIONALLY] ENCLOSED BY character
- The first character of the FIELDS TERMINATED BY and LINES TERMINATED BY values
- ASCII NUL (the zero-valued byte; what is actually written following the escape character is ASCII “0”, not a zero-valued byte)
The FIELDS TERMINATED BY, ENCLOSED BY, ESCAPED BY, or LINES TERMINATED BY characters
must be escaped so that you can read the file back in reliably. ASCII NUL is escaped to make it easier to view with some pagers.
The resulting file does not have to conform to SQL syntax, so nothing else need be escaped.
If the FIELDS ESCAPED BY character is empty, no characters are escaped and NULL is output as NULL, not \N. It is probably not a good idea to specify an empty escape character, particularly if field values in your data contain any of the characters in the list just given.
Here is an example that produces a file in the comma-separated values (CSV) format used by many programs:
SELECT a,b,a+b INTO OUTFILE '/tmp/result.txt'
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY '\n'
FROM test_table;
