In the late 90's I spent an enormous amount of time learning website programming such as HTML and CSS. Within a couple years, I was running a hosting company in an all linux environment. The ability to have server-side coded pages was getting more and more popular at that time (about 2003). The cost for services that had these technologies were very expensive and all the software was free online.
I started learning PHP/MySQL around that time and it was just launching version PHP 5, which was a completely different programming syntax. After spending about a year learning PHP in general, I was a little irritated that I had to re-learn it. At the time of this writing, PHP is now on version 7, which you guessed it, rewrote the syntax again. This irritation of mine is probably why I never liked the website design career path and ended up liking the administrator role a lot better.
Two sources that helped me in the design of the Keezer Kiosk which is all PHP and SQL:w3schools.com (https://www.w3schools.com/)
This site was helpful for the general reference for syntax and making sure what I was thinking is possible.
Tania Rascia's website - Article on building a simple CRUD database app
During the initial design of the Keezer Kiosk web-application, I was hacking code from all different places and had no idea on how to pull multiple programming lingos together. This article helped me understand a more component-built site, which later helped me with understanding the whole Gatsby and Netlify things.