So I'm a new junior dev, been working for around 4 months.
What's some advice from you've learnt from experience that you would give to someone in my position?

For context, I taught myself Java a while ago, was taught Python and some PHP recently and have patchy self taught knowledge of JavaScript.
So no degree and minimal formal training!
I have done 3 or so months of Ruby (self taught) doing back end web dev with Rails and soon am going to get involved with a small PHP and front end built from scratch.

Does anyone know a good book for learning PHP? I want to know more about back-end development and would like some recommendations. I've been programming mostly in Java before and also have experience with SQL, HTML and CSS.

If anyone could suggest a book or any kind of advice I would really appreciate it. I've found some interesting ones online like "PHP & MySQL Web Development – by Luke Welling & Laura Thompson", but would like to hear out first people who know more about this programming language.

Java vs Php for the back-end of a student project?