# Osquery: Consider joining against the users table
## Proper use of JOIN to return osquery data for users
Many an osquery user has encountered a situation like the following:
```
$ osqueryi
Using a virtual database. Need help, type '.help'
osquery> SELECT uid, name FROM chrome_extensions LIMIT 3;
+-----+--------------------------------------------+
| uid | name |
+-----+--------------------------------------------+
| 501 | Slides |
| 501 | Docs |
| 501 | 1Password extension (desktop app required) |
+-----+--------------------------------------------+
osquery>
$ sudo osqueryi
Using a virtual database. Need help, type '.help'
osquery> SELECT uid, name FROM chrome_extensions LIMIT 3;
W0519 09:35:27.624747 415233472 virtual_table.cpp:959] The chrome_extensions table returns data based on the current user by default, consider JOINing against the users table
W0519 09:35:27.625207 415233472 virtual_table.cpp:974] Please see the table documentation: https://osquery.io/schema/#chrome_extensions
```
Our query runs as expected when `osqueryi` is run as a normal user, but returns a warning message and no results when run as root via `sudo osqueryi`.
This same issue manifests on many tables that include a `uid` column:
- `authorized_keys`
- `chrome_extension_content_scripts`
- `chrome_extensions`
- `crashes`
- `docker_container_processes`
- `firefox_addons`
- `known_hosts`
- `opera_extensions`
- `safari_extensions`
- `shell_history`
- `user_ssh_keys`
### What’s going on here?
As stated in the error message, these tables return “data based on the current user by default”. When run as a normal user, the implementations know to look in paths relative to the user’s home directories. A query running as root does not know which directories to check.
### The solution
Show osquery which users to retrieve the data for. Typically this is achieved by a `JOIN` against the `users` table to retrieve data for every user on the system:
```
SELECT uid, name
FROM users CROSS JOIN chrome_extensions USING (uid)
```
Writing the query with this `JOIN` ensures that osquery first generates the list of users, and then provides the user `uid`s to the `chrome_extensions` table when generating that data.
Note: It is important to use `CROSS JOIN` as this tells the query optimizer not to reorder the evaluation of the tables. If we use a regular `JOIN` it is possible that reordering could result in the original error being encountered (because the `chrome_extensions` table generates with no `uid` in its context).