'mysql' Command not Connecting as used from PATH but Works if Full Path is Used

Not sure how to fix this but here is the description. I can run the command to a Lampstack MySQL installation like this and it works:

/opt/lampstack/mysql/bin/mysql -u root -p

And my PATH variable has this path in it, but yet this command doesn't work:

mysql -u root -p

Gives this error:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

The command asks for password but then gives the error.

I should note as well that running phpMyAdmin works fine at localhost:9090 with root and correct password.

Presumably, there are two MySQL installations getting confused, because I can run each command with --version and I get two distributions: 5.5.32 and 5.5.21.

This is a problem because I'm trying to use the Lampstack MySQL installation for a Django project. I have this configuration running on Windows but in an attempt to duplicate the environment on Ubuntu I've gotten a bit mixed up.

What is the best way to resolve this issue without removing the core MySQL on the Ubuntu system (and use the Lampstack one)?

NOTE

I discovered that the /var/run/mysqld/mysqld.sock doesn't actually exist and nor does the directory /var/run/mysqld. I'm not sure how to fix this so any assistance is appreciated.