Query output to a file gives access denied error

Question

I am trying to capture the output of a SQL query in MySQL, to a text file using the following query.

select count(predicate),subject from TableA group by subject into outfile '~/XYZ/output.txt';

I get the following error.

ERROR 1045 (28000): Access denied for user 'username'@'%' (using password: YES)

Any idea, where am I going wrong? Is it some permission related issue?

Answer 1

Outfile is it's own permission in mysql.

If you have ALL it's included.

But if you just have a safe collection such as SELECT, INSERT, UPDATE, DELETE, DROP, CREATE, but not OUTFILE, "into outfile" will not work in queries.

The reason for this is that accessing files from within MySQL, even for write purposes, has certain security risks, because if you access a file from mysql you can access any file the mysql user has access to, thereby bypassing user-based file permissions.

To get around this, you can run your query directly into the output of whatever shell/language you're using to run the sql with.

Here is a *nix example

>$ echo "select count(predicate),subject from TableA group by subject"  | mysql -u yourusername -p yourdatabasename > ~/XYZ/outputfile.txt

But do it all on one line without the "\" or use the "\" to escape the line break.

What's happening here is that you're running a query into the mysql client and it's spitting out the result, then you're directing the output to a file. So the file is never called from within mysql, it's called after mysql runs.

So use mysql to get the information and THEN dump the data to the file from your own user shell and you'll be fine.

Or find a way to get yourself the outfile mysql permission, either way.

Answer 2

If it's your system (you're admin), and you know how to secure it, this is how you enable those permissions.

USE mysql;
UPDATE user SET File_priv = 'Y' WHERE User = 'db_user';
FLUSH PRIVILEGES;