I would like to push sensor data from the raspberry pi to localhost phpmyadmin. I understand that I can install the mysql and phpmyadmin on the raspberry pi itself. But what I want is to access my local machine's database in phpmyadmin from the raspberry pi. Would it be possible?
Sure, as long as they're on the same network and you have granted proper permission, all you have to do is use the proper hostname or IP address of the MySQL server (what you call the local machine). In whatever utility or custom script you have that writes data, use the networked IP address instead of 127.0.0.1 or localhost for the database host.
Depending on how you've installed MySQL, you may not have a user that listens for non-local connections, incoming MySQL connections may be blocked at the firewall, or your MySQL server may not listen for incoming network connections.
You've asked about using phpMyAdmin from the Pi, accessing your other computer, which doesn't seem to make much sense to me (I'd think you'd want to run phpMyAdmin on your desktop computer, not a Pi), but if you've got a GUI and compatible web browser running on the Pi then you'd just have phpMyAdmin and the webserver run on the same desktop computer that has MySQL and access that hostname and folder from the Pi (such as http://192.0.2.15/phpmyadmin).
If you're planning to make the MySQL server itself public-facing, you should really re-think that decision unless you know why that's a bad idea and how to properly secure it (but that may not be a concern; for instance I have one at home that is available on the local network, but my router blocks any incoming connections from external sources).
Push sensor data from raspberry pi to local host phpmyadmin database