In MySQL, the data directory stores information managed by the MySQL server. Each subdirectory of the data directory is a database directory and corresponds to a database managed by the server.

If you ever need to find out where the data directory is located on your MySQL implementation, below are some options to try.

The @@datadir Variable

The easiest way to return the data directory is with the @@datadir variable.

Example:

SELECT @@datadir;

Result:

+--------------------------+
| @@datadir                |
+--------------------------+
| /opt/homebrew/var/mysql/ |
+--------------------------+

I installed MySQL via Homebrew, and the data directory location reflects that.

The SHOW VARIABLES Statement

The SHOW VARIABLES statement shows the values of MySQL system variables. MySQL contains a lot of system variables, but we can filter the results to just those we’re interested in.

Example:

SHOW VARIABLES WHERE Variable_Name LIKE "datadir";

Result:

+---------------+--------------------------+
| Variable_name | Value                    |
+---------------+--------------------------+
| datadir       | /opt/homebrew/var/mysql/ |
+---------------+--------------------------+

The data directory location is in the Value column. We can see the variable name in the Variable_name column. This is the variable we looked up in the previous example. This is also the variable name that we filtered our results on (i.e. with WHERE Variable_name LIKE "datadir").

We can modify our statement to expand the results returned. For example, we can return all rows where the variable name ends with dir:

SHOW VARIABLES WHERE Variable_Name LIKE "%dir";

Example result:

+-----------------------------+---------------------------------------------------------+
| Variable_name               | Value                                                   |
+-----------------------------+---------------------------------------------------------+
| basedir                     | /opt/homebrew/Cellar/mysql/8.0.29/                      |
| character_sets_dir          | /opt/homebrew/Cellar/mysql/8.0.29/share/mysql/charsets/ |
| datadir                     | /opt/homebrew/var/mysql/                                |
| innodb_data_home_dir        |                                                         |
| innodb_doublewrite_dir      |                                                         |
| innodb_log_group_home_dir   | ./                                                      |
| innodb_temp_tablespaces_dir | ./#innodb_temp/                                         |
| innodb_tmpdir               |                                                         |
| lc_messages_dir             | /opt/homebrew/Cellar/mysql/8.0.29/share/mysql/          |
| plugin_dir                  | /opt/homebrew/opt/mysql/lib/plugin/                     |
| replica_load_tmpdir         | /var/folders/nl/60kzsgdn4cgdmvz534n7bdxh0000gn/T/       |
| slave_load_tmpdir           | /var/folders/nl/60kzsgdn4cgdmvz534n7bdxh0000gn/T/       |
| tmpdir                      | /var/folders/nl/60kzsgdn4cgdmvz534n7bdxh0000gn/T/       |
+-----------------------------+---------------------------------------------------------+

From the Command Line

We can run the above statements from the command line if required.

For example on a Mac, we can open a new Terminal window and enter the following statement:

mysql -uYourUserName -p -e 'SELECT @@datadir'

Result:

Enter password: 
+--------------------------+
| @@datadir                |
+--------------------------+
| /opt/homebrew/var/mysql/ |
+--------------------------+

Where YourUserName is the username. In this example I used -p in order for the user to be prompted for the password.