PHP MySQL OUTFILE command

Question

If I use the following in a mysql_query command:

SELECT *
FROM mytable
INTO OUTFILE '/tmp/mytable.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n';

• Where is the tmp file relative to, to the MySQL database somehow or to the PHP file?
• If it does not exist will it be created?
• If I would like it to appear 1 folder up from the PHP file which does it, how would I do that?

Answer 1

According to The Documentation On Select, it's stored on the server and not on the client:

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.

And, more to the point:

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 other host than the server host, you normally cannot use SELECT ... INTO OUTFILE since there is no way to write a path to the file relative to the server host's file system.

So, don't use it in production to generate CSV files. Instead, build the CSV in PHP using fputcsv:

$result = $mysqli->query($sql);
if (!$result) {
    //SQL Error
}
$f = fopen('mycsv.csv', 'w');
if (!$f) {
    // Could not open file!
}
while ($row = $result->fetch_assoc()) {
    fputcsv($f, $row);
}
fclose($f);

Answer 2

Where is the tmp file relative to?

A: The file will have the result of the select * from mytable

If it does not exist will it be created?

A: yes

If I would like it to appear 1 folder up from the php file which does it, how would I do that?

A: if you want one folder up from the fileYouAreRunning.php then make path like that: "../mytable.csv"